In Re the Marriage of: Robin Alan Tennant, petitioner, Appellant, vs. Melanie Sue Tennant, n/k/a Melanie Sue Greening, Respondent.

may not be cited except as provided by

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

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C6-98-832

In Re the Marriage of:

Robin Alan Tennant, petitioner,

Appellant,

vs.

Melanie Sue Tennant,

n/k/a Melanie Sue Greening,

Respondent.

 Filed November 10, 1998

 Reversed and remanded

 Thoreen, Judge*

 Concurring Specially, Lansing, Judge

Hennepin County District Court

File No. MF207213

Geraldine Carlen Steen, Beckman & Steen, 14550 Excelsior Boulevard, Suite 206, Minnetonka, MN 55345 (for appellant)

Burke J. Ellingson, Brendel & Zinn, Ltd., 46 East Fourth Street, Suite 804, St. Paul, MN 55101 (for respondent)

Considered and decided by Lansing, Presiding Judge, Klaphake, Judge, and Thoreen, Judge.

 U N P U B L I S H E D O P I N I O N

 THOREEN, Judge

The ALJ abused her discretion by failing to apply the Hortis/Valento offset formula to the parties' joint physical custody arrangement. We reverse and remand.

 FACTS

Appellant Robin Tennant and respondent Melanie (Tennant) Greening dissolved their eight-year marriage by stipulated agreement resulting in a July 1991 judgment. The parties have two children who were seven and three at the time of the dissolution. The parties agreed to joint custody "with the physical residence of the children with [respondent]," and the judgment and decree stated:

The parties shall have joint physical custody of the children according to the following schedule: Primary physical residence of the children * * * with [respondent] and [the children] shall spend every other weekend and one night a week with [appellant] with holidays and vacation time to be divided equally between the parties as they may agree.

The parties agreed that appellant would pay monthly child support of $450 per month. This was a downward departure from the guidelines, justified by giving respondent the benefit of the tax exemptions.

After both parties moved to Hennepin County, they filed their Dakota County judgment and decree there and sought the use of Hennepin County Court Services to resolve differences that arose as to the custodial arrangement and child support. By order filed April 1995, the parties agreed that appellant would pay temporary support based on the guidelines and agreed to use mediation to resolve their custody issues. Eventually, respondent withdrew from the mediation process. Cross-motions were filed in June and July 1997.

In an August 1997 order, the district court modified the parties' parenting schedule to conform to their agreement and practice as follows:

[Appellant] shall have the right to have the children on alternating weekends from Friday at approximately 4:30 p.m. to Monday at 8:00 a.m., each Monday from approximately 4:30 p.m. to Tuesday at 8:00 a.m. and each Tuesday from approximately 4:30 p.m. to Wednesday at 8:00 a.m.

Because neither party provided sufficient information, the court reserved the issue of child support.

In October 1997, after the parties were still unable to come to an agreement concerning child support, appellant filed a motion to reduce his child support from the temporary amount ordered in August 1995. After a contested administrative proceeding, the ALJ denied appellant's motion to modify and this appeal followed.

 D E C I S I O N

An appeal from an administrative hearing under chapter 518 is treated the same as an appeal from the district court; the same standards of review apply. Lee v. Lee, 459 N.W.2d 365, 368-69 (Minn. App. 1990), review denied (Minn. Oct. 18, 1990); Minn. Stat. § 518.5511, subd. 4(j) (Supp. 1997). We review an order denying modification under an abuse of discretion standard. Moylan v. Moylan, 384 N.W.2d 859, 864 (Minn. 1986). An order "respecting * * * support may be modified upon a showing" of changed circumstances that "makes the terms unreasonable and unfair." Minn. Stat. § 518.64, subd. 2 (Supp. 1997). The party moving to modify support must demonstrate both a substantial change in circumstances and unfairness of the existing obligation resulting from the change. Tuthill v. Tuthill, 399 N.W.2d 230, 232 (Minn. App. 1987). Circumstances are compared to those that supported the existing order. Wiese v. Wiese, 295 N.W.2d 371, 372 (Minn. 1980) (determining change of circumstances from those existing at time of dissolution or time of last modification).

Here, the judgment and decree is the proper starting point to determine if a change of circumstance supports modification of child support. Although the parties agreed to the April 1995 support order, their intention was that amount of support was temporary. The court ordered "temporary child support." The ALJ's reliance on this temporary order as the starting point was error. Temporary orders "[s]hall not prejudice the rights of the parties * * * which are to be adjudicated at subsequent hearings." Minn. Stat. § 518.131, subd. 9 (1996).

The parties agreed to joint custody with the primary residence of the children with respondent. They also agreed that appellant would pay less than guidelines support, and although the parties acknowledged the reduction was in part due to respondent's receipt of tax exemptions, it is not clear how they arrived at this reduced amount of child support.

Since the judgment and decree was entered, the record establishes the following changed circumstances: (1) the parties' custodial arrangement has evolved over the years to reflect a more equal allocation of time between the parties, consistent with their joint custody agreement,[1] and (2) the parties are no longer able to agree on an amount of child support. Based on this record, the ALJ's finding of no substantial change in circumstances is clearly erroneous. Cf. Buntje v. Buntje, 511 N.W.2d 479, 481 (Minn. App. 1994) (although not listed in statute, custody changes can be substantial change justifying modification); McNattin v. McNattin, 450 N.W.2d 169, 171 (Minn. App. 1990) (courts consider parties' agreement when determining whether change of circumstances occurred).

Minn. Stat. § 518.64 establishes a presumption that a support amount is unreasonable and unfair if

the application of the child support guidelines * * * 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(b)(1) (Supp. 1997). In joint custody cases, a parent's obligation to pay guidelines support applies only for the period of time that the other parent has custody. Tweeton v. Tweeton, 560 N.W.2d 746, 747 (Minn. App. 1997), review denied (Minn. May 28, 1997). Because in joint custody cases both parents have a support obligation, the obligation of the parent with the higher amount of support is reduced by the other parent's lesser amount of support. Valento v. Valento, 385 N.W.2d 860, 863 (Minn. App. 1986) (citing Hortis v. Hortis, 367 N.W.2d 633, 635-36 (Minn. App. 1985)), review denied (Minn. June 30, 1986).

Applying the guidelines to the parties' current circumstances requires recognition of their shared custody. See Tweeton, 560 N.W.2d at 747 (obligation to pay support exists only when other parent has custody); see also Ver Kuilen v. Ver Kuilen, 578 N.W.2d 790, 793 (Minn. App. 1998) (use of Hortis/Valento formula is "an application of the statutory guidelines"). The ALJ's refusal to apply Valento in these circumstances was an abuse of discretion. Based on the parties' joint custody and relying on the ALJ's net income findings, appellant established that the existing temporary order is presumptively unreasonable and unfair under section 518.64, subdivision 2(b). The application of the guidelines to the parties' current circumstances requires each parent to pay support for only the time the other parent has custody. See Valento, 385 N.W.2d at 863 (parties' support obligation is determined for period of time other parent has custody). The current order requires appellant to pay the entire amount of guidelines support, without any credit for the time that he has custody and without any support from respondent during the time he has custody.[2]

Respondent argues that the ALJ's finding that she pays more of the children's expenses is sufficient to support a deviation from guidelines support under a Valento calculation. While the ALJ found that respondent paid "virtually all other expenses of the children" over and above each party's "normal costs of having children stay with them," there is no finding of the actual cost of these expenses or finding that these additional expenses support an exception to the "[a]pplication of Valento in this circumstance." The ALJ found no changed circumstances, declined to apply Valento, and refused to modify the existing temporary order. The ALJ did not consider or make findings to support a deviation from the guidelines. See Minn. Stat. § 518.551, subd. 5(c), (h) (1996) (court may receive evidence on listed factors to determine if guidelines should be modified in particular case).

On remand, after application of Valento to the parties' circumstances, the ALJ may consider the statutory factors that justify a deviation from the guidelines. See Valento, 385 N.W.2d at 863 (support amount that was more than guidelines amount offset by each parent's obligation was upward departure requiring remand where findings did not address statutory factors that could justify departure).

 Reversed and remanded.

 LANSING, Judge (concurring specially).

I concur in the majority opinion insofar as it holds that the proper point from which to determine changed circumstances is the judgment and decree and not the temporary support order. For that reason, I agree that the case must be remanded for redetermination.

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

[1]In documents filed with the district court, appellant claimed that he had the children 40% of the time while respondent had the children 60% of the time. In his brief filed with this appeal, appellant claims a 50-50 division of time. At oral argument, respondent's counsel acknowledged an arrangement approaching an equal division of time.

[2] We choose not to calculate what the parties' obligations would be under Valento absent a finding of the actual custody division. On remand, a finding of how the parties divide their time is required prior to application of Valento.