TEX. FAM. CODE § 157.008(d). The burden of proof as to the affirmative defense provided by section 157.008 is on the obligor. See id. § 157.006. Thus, an obligor such as Mullen has the burden to prove that he provided “actual support” during a time of excess possession. The obligor can request reimbursement as a counterclaim or offset of “that support” against the claim of the obligee. The Family Code does not prescribe the quality of proof an obligor must provide as to support provided. See Curtis v. Curtis, 11 S.W.3d 466, 473 (Tex.App.—Tyler 2000, no pet.) (evaluating evidence of canceled checks and documentary evidence as well as testimony of an obligor as to amount of support provided), and cases cited therein; Buzbee v. Buzbee, 870 S.W.2d 335, 339-40 (Tex.App.—Waco 1994, no writ) (<HOLDING>). The Code does, however, plainly provide that
holding that where payments are made on past due support they must first be applied to  current child support installments due then to accrued and outstanding interest on  delinquent child support obligations and finally to the principal amount due on unpaid child support holding that the trial court lacked authority to renew spousal support payments pursuant to a motion that was filed after the expiration of time during which spousal support was required to be paid under the original judgment holding that the testimony of an obligor as to amount of payments was sufficient evidence to support findings of actual support paid holding merely that the evidence was sufficient to support the award of attorneys fees holding that obligor who is incarcerated for crime other than failure to pay support should be relieved of obligation unless obligor has other income or assets