T3 followed by T2 followed by T1  If this sequence is not followed then it may happen that Officer of one slab get benefited twice. Say an officer is having commission as 99,999,He must be get updated commision according to T2.But then 99,999*1.04=1,03998 and he again becomes eligible for next slab of commision. T3 followed by T2 followed by T1 will be check all border cases like above