Sadly, the proliferation of various switches, and their on/off positions varied between airlines, and within some airlines, between aircraft types.
Take the B707 and the Lockheed TriStar for example.
Trans World Airlines insisted that both of these types share common on/off switch positions, when they accepted new aircraft for delivery....ie: up (aft) = ON, down (forward) = OFF.
This was contrary to the 'standard' Boeing/Lockheed fit.
Not a problem, as all TWA aircraft were like this.
THEN, when these aircraft were sold, they joined other airlines fleets, where the switch positions were the 'standard' Boeing/Lockheed variety.
So, depending on which 707 or L1011 you were to operate on that particular day, the switch positions varied from the previous days ops.
This was not particularly a problem for experienced Captains/First Officers, but was a big problem for the brand new co-pilots under line training.
Clearly not a good situation, but they carried on regardless, sometimes in total confusion.