You can have lousy instructors skipping requirements anywhere and any time. According to the History of NAUI written chiefly by found Al Tillman, they knew that some instructors were giving out cards before students had completed the course from the very beginning (1960), and they knew there were cases where students got certification cards without doing any of the course at all. As a career educator, I can assure you that things like that go on in schools and colleges all over the world.
I taught both the table version of the OW course and the table version. Students who took the table version of the course learned to use tables with only the briefest of mentions of computers, and they then went out and dived using computers. The computer version tells the students what a generic computer does. The PADI version has an online simulator showing how things change on a generic computer as the diver ascends and descends during a dive. I can't guarantee that all instructors use that simulation in class, but it is part of the student materials.