(3)A Government servant who has compulsorily to wait for his posting to a particular post and whose period of compulsory waiting is treated as on duty under F. R. (9) (6) (b), shall be entitled to draw during the first six months of such waiting City Compensatory Allowance and during the entire period of such waiting House Rent Allowance at the rates admissible to him from time to time subject to the production of a certificate on the proforma prescribed below: