If from Engine first comes A1 and than A2, logically, S1 should come first and than S2------S11 (I do not dispute your information but if possible, please reconfirm).
***
It is sure that for Tatkal, extra coaches are not attached to any of the IR trains (it was a practice in the start).
When charting is done, in a number of trains, the coach...
more... position is updated for the day. In such cases, when one checks the status of his / her PNR after charting, the coach position may be seen.
Thanks!