A deferred compensation agreement is an agreement between a company and an employee that withholds paying some of the employee's salary. Obtain the necessary forms for a deferred compensation agreement, including the employee's acknowledgement of the agreement and an IRS Form W-4P.Use these forms to manage your retirement plan. Future benefits from the 457(b) Plan will reflect the amount of a participant's voluntary salary deferral contributions plus earnings. Vesting is immediate. Deferred comp plans can be a powerful retirement tool. County of San Diego. 457(b) Special 3-Year Catch-Up. Application.