I think Batch 3 customers would love to be thrown a bone.  I think the idea of all 3 module purchases getting upgraded to 4 modules is a great idea.  It is a solution that doesn't cost Bitsyncom very much (if Hashtech can build them with chip orders for 9BTC, I would guess at most 3BTC per module for Bitsyncom to produce them).  This also has the advantage of making the assembly process uniform (just like Batch 1 and 2 were only 3 modules).  

If that approach is taken, the obvious solution for 4 module customers is to have their price refunded down to 3 module price (i.e. 76BTC - if purchased with a powersupply) per unit.  However... that is a more expensive proposition... as that is real BTC being refunded.  Maybe something could be arranged with store credit... though I doubt that will be as popular, but won't be as expense for Bitsyncom.

My guess is that all Batch 3 customers would prefer and be happy with this solution rather than putting in a refund request for the whole amount.  This at least I think give batch 3 customers the belief that they have a chance for some level of return on investment.