The County offers a voluntary Deferred Compensation Plan in accordance with Section 457 of the Internal Revenue Code. The Contra Costa County Deferred Compensation Plan is a governmental.A voluntary retirement savings plan that provides quality investment options, investment educational programs and related services. The costs to purchase service credit fall into two categories, depending on the type of eligible credit. Purchases can be made with post-tax dollars. For more information on loans, contact the. Louisiana Deferred Compensation Plan at (800) 937-7604.