In the Matter of the Welfare of: S.R.

may not be cited except as provided by

Minn. Stat. § 480 A. 08, subd. 3 (1996).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C8-97-1776

In Re the Marriage of:

Kyle J. Worley, petitioner,

Appellant,

vs.

Janice Marie Worley, n/k/a

Janice Marie Koval,

Respondent.

 Filed April 14, 1998

 Affirmed

 Willis, Judge

Washington County District Court

File No. F4955217

Timothy S. Choal, 155 South Wabasha, Suite 103, St. Paul, MN 55107 (for appellant)

Edward W. Simonet, III, P.O. Box 16, 522 South 4th Street, Stillwater, MN 55082 and Sharon L. Buffington, 708 Vine Street, Hudson, WI 54016 (for respondent)

Considered and decided by Randall, Presiding Judge, Klaphake, Judge, and Willis, Judge.

 U N P U B L I S H E D O P I N I O N

 WILLIS, Judge

Appellant father challenges the district court's modification of child support to the guidelines amount. We affirm.

 FACTS

The marriage of Kyle Worley (Worley) and his wife, now known as Janice Koval (Koval), was dissolved in June 1996. The parties used mediation to reach agreements on issues that included child support and custody of their son, now age four. The mediated agreement, which was incorporated into the dissolution decree, provided that Worley would pay Koval $300 per month in child support[1] and $60 per month for daycare. Worley is a printer at a publishing company and the child support figure is significantly below the statutory guidelines amount for his income.

A year after the dissolution, Koval, a claims adjustor for an insurance company, moved to modify several aspects of the decree, including an increase in child support to the guidelines amount. Koval's motion did not identify grounds for the child support modification, but her accompanying affidavit stated that her income had decreased and her expenses had increased. At the motion hearing, however, Koval's counsel stated that the change in circumstances was Worley's switch from the night shift to the day shift at his work. By the terms of the decree, this change (which Koval stated she understood to have been intended to occur ten to twelve years after the dissolution) meant that Worley would receive joint physical custody, in turn affecting support. Worley appeared pro se at the hearing.

The court modified the decree to maintain Koval's sole physical custody, made some changes in the visitation schedule, and after making findings with regard to Worley's income, modified child support to the guidelines amount of $561.46 per month, plus $90 per month in daycare expenses. Worley appeals the modification of child support.

 D E C I S I O N

In his statement of the case, Worley challenged the district court's modification of visitation, but does not argue this issue in his brief and has therefore waived it. See Melina v. Chaplin, 327 N.W.2d 19, 20 (Minn. 1982). On appeal, Worley argues that Koval's motion should have been treated as a motion for amended findings under Minn. R. Civ. P. 52.02 and is therefore time-barred. Worley did not argue this issue below, and this court will therefore not consider it. See Thiele v. Stich, 425 N.W.2d 580, 582-83 (Minn. 1988). The sole remaining issue is modification of child support, which is within the district court's discretion and is reviewed only for an abuse of that discretion.[2] Kuronen v. Kuronen, 499 N.W.2d 51, 53 (Minn. App. 1993), review denied (Minn. June 22, 1993).

Worley argues that the district court was required to make findings on the statutory factors in Minn. Stat. § 518.64, subd. 2(a) (1996), citing Moylan v. Moylan, 384 N.W.2d 859, 865 (Minn. 1986). This holding of Moylan has been modified by subsequent amendments to the child-support statute. Rouland v. Thorson, 542 N.W.2d 681, 683-84 (Minn. App. 1996). The amended statute provides:

It is presumed that there has been a substantial change in circumstances under [one of three of the statutory factors] and the terms of a current support order shall be rebuttably presumed to be unreasonable and unfair if the application of the child support guidelines in section 518.551, subdivision 5, to the current circumstances of the parties results in a calculated court order that is at least 20 percent and at least $50 per month higher or lower than the current support order.

Minn. Stat. § 518.64, subd. 2(a). Applying the amended statute, we have held that, no matter which party seeks to modify support to the guidelines amount, the party seeking a deviation from the guidelines bears the burden of proof. Rouland, 542 N.W.2d at 684.[3]

Worley argues that the ground on which Koval's written motion for modification was based, that is, a decrease in her income and an increase in her expenses, was not supported by the record. The court made no findings as to Koval's income and expenses, but it was not required to do so. To award support at the guidelines level, a court need only make "findings concerning the amount of the obligor's income used as the basis for the guidelines calculation and any other significant evidentiary factors affecting the determination of child support." Minn. Stat. § 518.551, subd. 5(i) (1996) (emphasis added). The record shows that Worley was paying child support in an amount more than 20 percent and $50 below guidelines support. Under section 518.64, subdivision 2(a), therefore, Worley bore the burden of providing a reason to maintain support at the level he had been paying. The district court has the responsibility

to decide cases in accordance with law, and that responsibility is not to be diluted by counsel's oversights, lack of research, failure to specify issues or to cite relevant authorities.

 State v. Hannuksela, 452 N.W.2d 668, 673 n.7 (Minn. 1990) (citation and internal quotation omitted).[4]

The district court did not find explicitly that Worley failed to carry his burden of defending a deviation from the child-support guidelines. But the only justification Worley has provided is that the parties stipulated to an amount less than the guidelines provide. A stipulation to a downward deviation from the guidelines does not preclude a motion for modification upon a showing of changed circumstances. See McNattin v. McNattin, 450 N.W.2d 169, 171-72 (Minn. App. 1990) (stating that wife's stipulated agreement not to seek child support did not preclude her from seeking such support upon showing of changed circumstances). In this case, the changed circumstances were established by a statutory presumption that the court had a responsibility to apply. See Rouland, 542 N.W.2d at 684; Hannuksela, 452 N.W.2d at 673 n.7. Stipulations for child support are given less weight than other stipulations because child support is a legal obligation that "relates to non-bargainable interests of children." Aumock v. Aumock, 410 N.W.2d 420, 421 (Minn. App. 1987); see also Murray v. Murray, 425 N.W.2d 315, 317 (Minn. App. 1988). The legislature has demonstrated a strong preference in favor of support at the guidelines level, and we conclude that the district court did not abuse its discretion in determining implicitly that Worley had failed to rebut the presumption that the stipulated level of support was unreasonable and unfair or to prove that requiring him to pay guidelines support would be inequitable under the circumstances.[5]

Finally, Worley argues that the court miscalculated his income. A district court's determination of income for child-support purposes will be upheld if it has a reasonable basis in fact. Strauch v. Strauch, 401 N.W.2d 444, 448 (Minn. App. 1987). A court's choice of calculation methods is generally upheld absent an abuse of discretion. See, e.g., Quick v. Quick, 381 N.W.2d 5, 9 (Minn. App. 1986) (concluding court did not abuse discretion in basing award on self-employed obligor's past earnings and earning potential). The district court calculated Worley's income based on his 1996 W-2 form; Worley argues that the court should have worked from the two 1997 pay stubs he submitted. Those stubs show $25 per week in 401(k) contributions and $7.75 in what appear to be health insurance contributions, both of which may be deducted in calculating net income for purposes of determining guidelines support.[6] Minn. Stat. § 518.551(b) (1996). But the pay stubs also show Worley earning approximately $20 more per week in 1997 than in 1996. We conclude that the district court did not abuse its discretion in determining Worley's income based on complete information for 1996 rather than on two individual pay periods in 1997, and it appears that even if the court did fail to account for certain deductions, the increase in Worley's income would render de minimis any change in his obligation resulting from the deductions. We therefore conclude that the district court's award is supported by a reasonable basis in fact. See Strauch, 401 N.W.2d at 448.

  Affirmed.

[ ]1 The agreement provided that Worley would pay Koval $75 per week. In months with more than four weeks, Worley credited the extra $75 against health insurance and daycare obligations.

[ ] 2 Worley does not explicitly argue that the district court erred in imposing a $30 increase in monthly daycare costs, apparently in response to a showing in Koval's affidavit that the cost of the care had increased from $240 to $270 per month, although he does claim that the increase was offset by a decrease in Koval's overall expenses. See Minn. Stat. § 518.551, subd. 5(b) (1996) (providing that court will allocate child-care costs in proportion to net income after child support).

[ ]3 Even before the amendment, this court had held that "almost any change in circumstances" could justify a modification of child support when the award was "well below" the statutory guidelines. Murray v. Murray, 425 N.W.2d 315, 317 (Minn. App. 1988) (quoting Compart v. Compart, 417 N.W.2d 658, 662 (Minn. App. 1988)).

[ ]4Hannuksela and its progeny have placed this duty on appellate courts without specifically extending it to district courts. But it would be illogical to prohibit district courts from applying established law sua sponte when Hannuksela would require this court to apply the law correctly on appeal.

[ ] 5 Some courts have emphasized that the setting of child support involves a balancing of equities or "barter concerning child support, spousal maintenance, and property settlement." McNattin, 450 N.W.2d at 171 (quoting O'Connor v. O'Connor, 386 N.W.2d 395, 398 (Minn. App. 1986)); see also Brugger v. Brugger, 303 Minn. 488, 492-94, 229 N.W.2d 131, 135-36 (1975) (noting that dissolution decrees can involve many intertwined issues). But in this case, both parties permanently waived spousal maintenance, what property there was to distribute was either divided equally or allocated according to possession, and the judge ruling on the motion for modification also had presided over the original dissolution.

[ ] 6 Worley appears to argue that the court should have based its income calculations on his net pay as shown on the pay stubs, but this figure does not include $76.89 per week in credit union and life insurance deductions that are included in net income under the statute for the purpose of establishing child support.