If they are union (don't think so) but there are ways around that. 1. Paid as line pilot, plus X amount of dollars for special 1 day consulting in the office. (kinda like alpo dudes)
2. Had it happen at another airline, had 2 two different types of equipment, one payscale. Company had trouble hiring, so they arbitrarily increased one of the the aircraft payscales by 10.00/hr. Union tried to fight it and get everyone the raise, there was a loophole on size classification, which enabled the company to break out the other airplane, and as long as they paid more than what the min. payscale was, they were ok. The payscales are the min the company must pay. They can pay more, as long as the do it evenly across the board to all affected members..