I`ve taken the liberty of bolding the pertinant bit of your post, that wasn`t what you were saying earlier now was it.
Simon just said that he has done hundreds of jobs which involve rearranging DACS pairings to free up a pair to provide ADSL service for somebody.
Obviously it comes down to a case of
when possible. If you have, say, 50 pairs running to a particular area, 30 of which are in use by subscribers with ADSL, ISDN, Redcare etc. and the other 20 pairs are serving 40 PSTN-only subscribers via DACS, then there just isn't any way to rearrange things to provide another ADSL line without running in additional cables.
But as I read your earlier post you were suggesting that BT/OpenReach will refuse to even attempt to provide ADSL service to somebody whose line is already on DACS. (By the way, it's not
just DACS to consider; in many districts further from the exchange there may be local line concentrators in use too.)
Now, if you're saying that some of the script-droids you talk to in India when trying to request things don't have a clue and will try to say you can't have something when you can, that's a different matter.....