FWIW, in the club environment where multiple users are constantly adding new engines to the system, this is where we typically see the problem that a previous user has set an ID say like 49 (typically an SP Daylight) to Legacy mode, but this user has only the older TMCC engine. So they pickup the remote, hit ENG 49, an their TMCC engine does not respond.
Even in my own fleet at home, this happens. I try to typically use the first 2 or last 2 digits of the cab number, and bottom line, in a big enough fleet, you might have 2 engines that simply would result in the same ID. One might be TMCC, one might be Legacy, and so you end up doing this switch mode edit or choosing a number that doesn't correspond to the cab number and I tend to forget it.
