The 1st and 3rd question in your above post I am right now unable to answer but will surely answer once I receive any information about It. Also would appreciate if you can post your findings here.
For your second question aside to the ways of resolving and reasons of low ASR mentioned by my friends I have few more inputs for your reference:-
A. please check the routing at both near and far end if it is another operator please send the traces of call failures for resolving the routing issues. Some times accidentally the other operator opens a wrong code towards your switch which impatcs your incoming and outgoing ASR due to repetitive attempts by the calling operator.
B. check for possible Electrical E1s or Voice quality issue creating E1s because the ASRs is hit incase the calling party hears a weird tone in place of CRBT and he drops the call.
C. The customers who are making mostly missed calls should be promoted to make outgoing calls in synch with your marketing team.
D. Check the Signalling report and see if a particular Signaling link is zero utilized because this signaling link makes your call unsuccessful if it is fluctuauting and hence reduction in ASR.
E. Check for your connectivity between BSC and MSC may be a possiblity that the Voice quality and the E1 Cross connection issue is lying at a BSC route and hence reducing your overall ASR. This issue I identified after beating every bush in my network. 🙂
These are the few wierdest possiblities i observed while resolving low ASR concerns.