The story goes like this. Apparently when the ATAGS was announced by the MoD , it was a collaborative effort by DRDO & the development cum production partners ( Tata Power & Bharat Forge ) only. The IA didn't have any role to play in it. Why? I've no clue.
Cut to the trials & the release of the PSQRs where the IA specified the weight & certain other modifications which is being carried out & trialed & on & on as we speak.
I & a few others had a huge argument with the guy who came up with this story on another forum . Tried looking online but there was nothing to corroborate his version. Subsequently Indranil , Rohit Vats & other BRF guys on Twitter released information which basically corroborated that guy's version.
So long story short , DRDO & DCPP commence a project sanctioned by the MoD with literally zero participation by the IA. As the project nears successful completion , the IA gets into the act & comes up with its requirements which though seemingly inferior to what the DRDO has come up with , will prevail as it should & must for they are the users.
Currently that's where we are w.r.t the ATAGS / TGS saga. If it reminds you a bit of the early days of the LCA , HTT-40 & other such aviation programs before Manohar Parrikar drilled sense into the IAF & brought them on board to take ownership of such projects , you aren't mistaken.
Story of how we run our defence programs by & large though it seems to be coming to an end now which I see as a huge tragedy for it robs us of much needed entertainment , what with the IN which was always a forward looking service fully attuned to local vendors - their strengths & weaknesses & how to graduate their programs technology wise , to the IAF which came on board during MP's tenure to the IA which is gradually coming on board if it's already not on boarded w.r.t the many ongoing developmental programs pertaining to the IA .