Thanks for prompt reply please. In my opinion, in this case my 2nd & 3rd ACP both should be from 01 Sep 2008. As 2nd ACP granted to me on 5.6.2006 already cancelled by our office and arrears granted on this account has been withdrawn/adjusted during claiming 6th Pay commission arrears from 01.01.2006 to Sep 2008. Moreover, Both the pay scales of 5000-8000 & 5500-9000 have been merged wef 01.01.2006 in the scale of 9300-34800. In other words, I am working as Steno Gde-II wef 05.06.1987 in the pay scale of 5000-8000 till today. As such, I should be eligible for my 2nd and 3rd ACP from 01 Sep 2008.