I get it that there is more work involved now, but shouldn't the TA factor in future costs when originally pricing the tickets?
What if his rent went up now, can he ask prepaid clients from 6 months ago for another $20? What if they asked for $500, not $75, where do you draw the line when/how/who can come back for more money down the line?
Take a step back for a moment. There are several nuances that should be addressed.
1) Halachically. When the payment is made for a service or a purchase, exactly what is being purchased should ideally be clearly defined. Is it? If it was and something changes radically, was it inside the expectations of both parties or outside it? If it was a relatively normal occurrence, it goes without saying (or should) that it is included in the original agreement, but what about where it isn't? It is possible that there is no achrayus for the original agreement, at which point the agreement is either botul or at least must be renegotiated (it is possible that even when botul, payment must be made for services rendered this far).
2) Dina Dmalchusa. If the changes are governed then all agreements follow those rules.
3) Customer Service - call this the possibility of taking a loss in order to justify the higher prices all those other times. What does the higher cost justify if not the possibility of losing time/money for the sake of reliability? On the other hand, maybe they don't care, or maybe they do care but this was waaaay out of the ordinary. I know in Israel the average worker cares more about the bottom line than the image they portray.
One example of an erliche worker I know - a computer technician (not me) - makes it clear when money will need to be spent and for how much. The diagnostic price is clearly defined. If it will take more than that, the owner is given the chance to back out at each stage. If a part will take an undefined amount of time to arrive, he says so, and he separates the cost of the part (paid up front) and the cost of the install (in case the customer gives up after three weeks). RBs is fond of quoting the Chofetz Chaim somewhere, who exhorts all workers to define as much as possible in advance - this is the way to go. No expectations, no disappointment...
