When an order has been entered which provides for payment of child support and the legal custodian places physical custody of the child with any person, subject to the provisions of the Oklahoma Children’s Code or this title, without obtaining a modification of the order to change legal custody, the placement of the physical custody, by operation of law, shall create a presumption that such person with whom the child was placed has legal physical custody of the child for the purposes of the payment of child support and the obligee shall remit such child support obligation to the person with whom the placement was made.