SetMCTimeTable - maximum number of timetable groups?

[paulper]

I've got over 550 timetables set, but the latest batch I added took the total number of timetable groups to 17 and now the SetMCTimeTable driver command by Pguy won't load in either Surveyor or Driver:

I don't believe it's the total number of timetables that are the issue. If I delete that last group of timetables it will work again. Is there meant to be a cap on the amount of timetable groups?

Thanks,
Paul