Contributions of employees shall be made by payroll deductions. Every included employee shall be considered to consent to payroll deductions. It is of no consequence that a payroll deduction may cause the compensation paid in cash to an employee to be reduced below the minimum required by law. Payment of an employee's compensation, less payroll deductions, is a full and complete discharge and satisfaction of all claims and demands by the employee relating to remuneration of services during the period covered by the payment, except with respect to the benefits provided under the plan.