In Spivey v. Furtado (1966) 242 Cal. App. 2d 259, an obligor-father paid, on his own initiative, his minor children's college tuitions and living expenses, in lieu of part of his child support obligation to the mother. During the time the father reduced payments to the mother, the children were away at college and no longer living with the mother. (Spivey, supra, 242 Cal. App. 2d at pages 265-266.) Nevertheless, under the terms of the parties' divorce decree, the father's child support obligation continued to accrue while the children were under the age of majority, then 21. (Spivey, supra, 242 Cal. App. 2d at pages 261-262.) The Spivey court held that the trial court did not abuse its discretion in denying the obligor-father's estate credit against the arrears, particularly where there was no evidence that the mother had agreed to credit the substituted payments against the arrears. (Spivey, supra, 242 Cal. App. 2d at pages 265-266.) The Spivey court noted that substituted payments should not be easily permitted, because "a judgment of a court should not be considered alterable by a party." It further noted that, "one of the reasons against lightly allowing substituted payments is that the father may thereby obtain a measure of control of the children against the decree . . . and acquire, to the mother's disadvantage, an aspect of benevolence for doing that which the court has required him to do." (Spivey, supra, 242 Cal. App. 2d at page 266.)