This reminds me... it is not just the instructor who is involved with the student’s skills. Other students are too.
When I did my 60m CCR course there was another student who had a 50m OC trimix qualification. He had done it with an instructor known to the instructor we were both taking the course with. So he is doing 60m OC and me 60m CC. It turned out he was not up to it, hadn’t really done much since the previous qualification and suffered from some skills rot. The delay meant I had to come back another day to finish the course.
This was nobody’s fault, just illustrates that progression is not strictly forwards. Qualified at level X does not mean able to take a course for X plus one, or possibly even at X.
For me, this reinforces the need for a more intensive dryland and underwater interview. This would help the instructor scope what students can be grouped together for the most efficient outcomes for instruction and student expectation. I realize this is a difficult proposal and I’m sure if I were running a dive center I could make equal and opposite arguments why mandatory UW interviews complicate matters. This is why I think WRSTC should step in and impose the requirement for technical training. That would recalibrate the industry with common parameters so as to not jeopardize student draw and profit.