I'd ask 15m, and except 15m. If the transfer was to fall through, and Szmodics sulked ( I very much doubt it ), as people have regularly said, we wouldn't see much of the money for replacements anyway. Only the Venkys would loose.
If what the rovers want is more than Ipswich will pay, then jog on. It could just as easily be that Ipswich are holding out for the court case to force the Rovers into selling for an overly cheap bid. Whatever, it is all speculation.