(k) Modification
(5) In proceedings for the modification of a child support award pursuant to the provisions of this Code section, the court may award attorney’s fees, costs, and expenses of litigation to the prevailing party as the interests of justice may require. Where a custodial parent prevails in an upward modification of child support based upon the noncustodial parent’s failure to be available and willing to exercise court ordered visitation, reasonable and necessary attorney’s fees and expenses of litigation shall be awarded to the custodial parent.