By course standards the last descent should be no line/without visual reference...
It may have been - that was 4 years ago. I bet we just turned our backs to the line.
That as all too often comes down to poor instruction. Proper ascents and descents are supposed to be taught, briefed, debriefed. Pressure, volume and buoyancy is meant to be taught, discussed, examined and reinforced in practice. From your description it sounds like too many people in the class which again boils down to poor judgement of the instructor.
In our case, I don't blame the instructor. I felt he did what he could and there were dive masters. I think there were just others in more need and I felt comfortable with what I was doing. I might put some blame on the LDS for allowing so many students, but that's the name of the game.
That's why SB is such a valuable resource. We can continue to learn, re-ask the questions if necessary. It's the expertise of the professionals and long-time divers here that help us get to where we need to be to be safe and responsible divers. All of this must be practiced in the water, but it's definitely good knowledge.
---------- Post added July 13th, 2014 at 09:56 AM ----------
Tatiana,
I would recommend PADI's Peak Performance Buoyancy (or equivalent with another agency if they have one). That class brought a lot of clarity to buoyancy for me, which I felt not only helped me with maintaining position in the water, but also on ascent/descent.