How could a company pay back some money to clients for selling a software (Is it a form of sue?). Could you explain this? It's not like when we buy something and we get a bad product and then you ask the seller to pay you back some money, right? That's quite funny. Most of the time the seller won't even care about whether or not that thing you've bought satisfies you. You're the one who wants it, why don't you check it first before you buy it. Or if the sellers wants to take that responsibility over it, what they most likely going to do is to give you the new stuff as the replacement. But in the case of a company selling some software why would they pay consumers money instead of them being paid? It also doesn't look like the software can't be fixed for the defect.
By the way, is the payment to the client that huge? It seems pretty serious after all (that hurry people going into meeting room with the client, that invisible argument/blame game among the team, that sweat, that irritated feeling, etc. ). Note that this is about selling the software, not particularly the software development contract with the clients.