Defense to Support if Income Different

As to cases filed after the effective date of this section, in any action for paternity, guardianship, child support, divorce, or separate maintenance, in which there is a minor child or minor children and for which there is no previous order (temporary or permanent) for child support, the court may in such cases enter an order for child support effective nunc pro tunc to the date of the filing of the complaint but not exceeding one

(1)year; provided, however, that reasonable provisions shall be made for payment of such amounts, if paid as ordered. The obligor may raise as a defense to such entry nunc pro tunc that the obligors income between the time of filing the complaint and the date of the order was such that during such period the obligor would have been unable to pay such child support or could only have reasonably paid reduced child support during such period.