Well, You'll be appointed on 16 scale as advertised but one thing is worth mentioning here, It was told earlier that all of the senior Inspector IRs are going to retire in coming few years as they've completed their whole service on the same grade.! :p
So, don't expect any promotion if selected.
We've a precedence about this, last year or year before those on 16 scale were promoted to 17 grade but they didn't get the new designation which is Superintendent i guess. It was in the newspaper they quoted "FBR made joke out of its 16 scale officers" :p
But still, we can hope that they'll realize how this policy will demoralize the young blood they are about to induct and will device new or amend this policy. InshAllah

I've sent my documents with this hope. Baqi sab Allah k Hath main
Ciao