It's been a long time since I was certified, but we were never taught anything other than the flutter kick in the OW or AOW course. Buoyancy was basically the fin pivot and picking a spot on the side of the pool and using your breathing to maintain your depth with one foot. Nothing in open water. Good Buoyancy control and proper kicking techniques were picked up by watching videos and when I took my advanced nitrox course. As with anything else, if you don't dive enough to keep in practice you will never perfect the techniques. You can't do it if you only dive one or two weeks a year on vacation. A pool refresher course is OK, but not the same as diving in the ocean. Thank goodness I now live in Oahu and dive just about every weekend!