In Re the Matter of the Paternity of C.M.N. and A.S.N, Terry Nyblom, Appellant, vs. Christina Cunningham, Respondent.

may not be cited except as provided by

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

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C8-97-1681

In Re the Matter of the Paternity of C.M.N. and A.S.N,

Terry Nyblom,

Appellant,

vs.

Christina Cunningham,

Respondent.

 Filed March 10, 1998

 Affirmed

 Mansur, Judge*

Ramsey County District Court

File No. F188517644

Steven T. Hennek, Lawrence D. Olson & Associates, P.A., 2860 Snelling Avenue North, St. Paul, MN 55113 (for appellant)

Dyan L. Campbell, 1102 Grand Avenue, St. Paul, MN 55105 (for respondent)

Considered and decided by Kalitowski, Presiding Judge, Davies, Judge, and Mansur, Judge.

*Retired judge of the district court, serving as judge of the Minnesota Court of Appeals by appointment pursuant to Minn. Const. art. VI, § 10.

 U N P U B L I S H E D O P I N I O N

 MANSUR, Judge

Appellant Terry Nyblom challenges the district court's determination of his child support obligations (including child care contribution), arguing that the district court erred in determining the amount of child support and increasing his child care contribution. We affirm.

 D E C I S I O N

Modification of child support is within the district court's discretion and will not be reversed absent an abuse of discretion. Rouland v. Thorson, 542 N.W.2d 681, 683 (Minn. App. 1996). Findings of fact will not be disturbed unless clearly erroneous. Minn. R. Civ. P. 52.01.

 I.

A child support order may be modified upon showing that the terms of the order are unreasonable and unfair because of one or more of the factors enumerated in Minn. Stat. § 518.64, subd. 2(a) (1996). Among the factors relevant here are: (1) substantially increased or decreased earnings of a party; and (2) substantially increased or decreased need of a party or the child or children. Id.

Appellant argues that the district court erred in not reducing his child support obligation based on the formula set forth in Valento v. Valento, 385 N.W.2d 860 (Minn. App. 1986), review denied (Minn. June 30, 1986), and Tweenton v. Tweenton, 560 N.W.2d 746 (Minn. App. 1997), review denied (Minn. May 28, 1997). Because the argument was not raised before the district court, we will not consider it. See Thiele v. Stich, 425 N.W.2d 580, 582 (Minn. 1988) (generally, this court will not consider issues not considered and decided by the district court).

Appellant also argues that the district court erred in not deviating downward from the support guidelines. He contends that he is entitled to a downward departure because he incurs more expenses in caring for the children while respondent works the 3:00 to 11:00 p.m. shift. The child support statute specifically addresses this issue:

The court may allow the noncustodial parent to care for the child while the custodial parent is working, as provided in section 518.175, subdivision 8. Allowing the noncustodial parent to care for the child under section 518.175, subdivision 8, is not a reason to deviate from the support guidelines.

Minn. Stat. § 518.551, subd. 5(b) (1996) (emphasis added). Based on Minn. Stat. § 518.551, subd. 5(b), we conclude that the district court did not abuse its discretion in not ordering a downward departure.

Additionally, appellant argues that the district court erred in disallowing the deduction for his tools used in his business in determining his net monthly income. An obligor is entitled to a deduction for business debts related to the production of income. Stevens County Social Serv. Dep't v. Banken, 403 N.W.2d 693, 697 (Minn. App. 1987). The district court noted that appellant is entitled to a deduction for his tools, but disallowed it because appellant failed to present adequate evidence. The record supports the district court's finding. Cf. Taflin v. Taflin, 366 N.W.2d 315, 319 (Minn. App. 1985) (party "will not be heard to complain" where party's inadequate documentation leads, in part, to denial of party's motion to modify support).

Finally, appellant argues that the district court should determine his income based on his 1997 pay stubs, rather than his 1996 W-2 form. In Thomas v. Thomas, 407 N.W.2d 124, 127 (Minn. App. 1987), this court held that because the figures for the first half of 1986 were available, they should have been used instead of the husband's 1985 tax return. Here, appellant submitted only two pay stubs from March 1997. Because of lack of information concerning appellant's current income and dispute regarding appellant's incentive pay, we conclude that the district court did not err when it used his 1996 W-2 form in determining his current net income. See Ronay v. Ronay, 369 N.W.2d 6, 10 (Minn. App. 1985) (a party's earning history may be considered in determining net income for child support purposes).

 II.

Appellant argues that the district court erred in increasing his day care contribution. Under Minn. Stat. § 518.551, subd. 5(b), an obligor's contribution to child care expenses may be modified if there is a substantial increase or decrease in existing work-related child care expenses. The district court found respondent's child care expenses for 1996 were $156.66 per month and that her current expenses have increased to $800 per month. Based on this work-related increase in child care expenses, we conclude that the district court acted within its discretion in modifying appellant's child care contributions.

Appellant argues that because he takes care of the children when respondent works the 3:00 to 11:00 p.m. shift, the day care expenses should be decreased, not increased. The district court's finding was based on respondent's testimony. On witnesses' credibility and their testimony, this court accords great deference to the district court's determination. In re Welfare of M.D.O., 462 N.W.2d 370, 374-75 (Minn. 1990). We conclude that the district court did not abuse its discretion in increasing appellant's share of the child care obligation.

  Affirmed.