As an instructor, I could not disagree with you more. Purchasing a class is purchasing training, not certification (as your timer implies). I have spent many extra hours with students outside of the normal class schedule. Also, I only teach individual classes.
With these two things in mind, I have withheld OW certification from two people (granting PADI Scuba Diver status instead).
I am willing to spend extra time with students, but my time isn't endless. I have other things to do besides repeat a task until I'm blue in the face. Diving isn't very difficult. I try to act as a guide more than an instructor, but if you don't get it, you should find another hobby.
If your jobs called and said you need to work weekends for the next few months, and, by the way, you won't get paid for it, what would you say? Most instructors teach for the pleasure of teaching (with the exception of the bulk class instructors) and have a regular life. Teaching diving is a way to share the underwater world with people and make friends. Instructors usually don't drive Carrera's or Range Rovers. I don't even break even from my own expenses. To think that their time is unlimited and that you are PURCHASING CERTIFICATION is Bull POOP. You purchase training, either you get it, or you don't.
Cheers,
Jamie
MSDT 176787