Joe Hamilton Prods. Inc. is claiming at least $ 10 million in damages from Lorimar Distribution Intl. Inc. for allegedly improper computation of distribution fees for the series “Mama’s Family.”In a complaint filed in Los Angeles Superior Court, Hamilton Prods. said Lorimar had kept more than the contracted-for 18% of gross receipts specified in a February 1986 agreement. Lorimar was supposed to pay its distribution agents (or “barter agents”) out of its 18%, the suit said, but instead paid them out of series revenue after deducting its fee. Hamilton Prods. also complained that Lorimar failed to provide promised accountings or allow access to books and records. The suit also seeks unspecified punitive damages. Lorimar could not be reached for comment last night.