It really depends on the instructor.
For example, my PPB class consisted of my instructor putting weight on me, taking it back off, giving me a light and taking it back off . . . at the end of it, I was confused and hadn't learned much. On the other hand, the one my husband teaches includes going through a proper formal weight check and then playing with weight placement, to optimize horizontal trim. You go over the configuration of your own gear and how best to use it. You work on posture, and how changing the position of body parts affects your trim. You practice controlled descents and ascents, and holding accurate stops. It's still only what you can accomplish in two dives, but there's enough material there that the students seem to think it was worth doing.
For example, my PPB class consisted of my instructor putting weight on me, taking it back off, giving me a light and taking it back off . . . at the end of it, I was confused and hadn't learned much. On the other hand, the one my husband teaches includes going through a proper formal weight check and then playing with weight placement, to optimize horizontal trim. You go over the configuration of your own gear and how best to use it. You work on posture, and how changing the position of body parts affects your trim. You practice controlled descents and ascents, and holding accurate stops. It's still only what you can accomplish in two dives, but there's enough material there that the students seem to think it was worth doing.