Deputation

I was on deputation with GRSE Ltd, Kolkata wef 02 Apr 03 to 01 Jul 06. GRSE LTD is a PSU under the MoD. I had opted for the army rates of pay and allces during my period of deputation. Please let me know whether I will be paid arrears from 01 Jan 06 to 01 Jul 06 at PB 4 rates or otherwise.