Before any person authorized under rule 23 signs a cheque, he shall satisfy himself that the sum for which the cheque is drawn is-
(i) required for a purpose or work specifically sanctioned by the proper authority and covered by a current budget grant; and
(ii) required for any payment referred to and specified under section 28:
PROVIDED that in the absence of a current budget grant the Corporation may authorize payment either generally or for any particular case :
PROVIDED FURTHER that the payment of benefits to insured persons under the provisions of the Act and of the pay and allowances of duly sanctioned posts shall not be withheld for want of a sanctioned budget grant.