For the most part, American Universities were established after railroad time tables were a thing…and in the US Latin and the other liberal arts were never the primary curriculum at most US universities, so cum tempore might as well be Latin.

Yep I even had one professor who locked the door at the start of class. You either had to pound on the door to get in or accept defeat. Most people just walked away unless it was an exam day

UC Berkeley had this as well, at least as of the class of 2010. I think it was called "berkeley time" or something along those lines.