Section 5(2) in The Indian Administrative Service (Pay) Rules, 2007
(2)Subject to the provisions of Clauses 2 and 3 of Schedule I, in the case of a promoted officer or an officer appointed by selection the increments shall accrue on completion of each year of qualifying service from the date his pay has been fixed in accordance with the provisions contained in schedule I and the same principles shall apply in cases where appointment to the service is preceded by officiation on a cadre post :Provided that the increments thus falling due shall accrue on the first day of the month in which they would have accrued :Provided further that for the purpose of calculating one year's service for drawing of increment, broken period of service rendered in a cadre post shall be taken into account.
