Within each agency that's true, but a PADI instructor can not add a requirement to make a dive with effective buoyancy control and no rototilling, a NAUI instructor can and should.
Yes, but you have to compare the apples to apples. You seem to be switching your argument back and forth. If you are going to cite minimum PADI standards to counter R0gue's statement that he can have a student perform most skills while neutrally buoyant, then you should be citing the minimum NAUI standards too.
There is no doubt that you can add to your standards (congratulations). I am just stating that there are plenty of opportunities in the PADI standards to get the students to maintain neutral buoyancy. There is the 50 yard underwater swim, which specifically states "Swim underwater with scuba equipment while maintaining
control of both direction and
depth, properly equalizing the ears and mask to accommodate depth changes."
If a student is "rototilling" they won't be able to maintain depth and direction. If they are going up down and all round, then they have not demonstrated "mastery" of the skill.
Each confined water dive has a "Fun and Skills Practice Plan sufficient time for practice exercises, games and remedial training." I could weigh down hoola hoops and have neutral buoyancy contests, etc.
Each OW dive has an "Exploration" part: The instructor manual states "... the novice is learning and assimilating a great deal, such as
buoyancy control..." Which by the way, the exploration portion of the dives have no pre-defined time limit.
Then there are also the "excursion dives". The definition of which is: An excursion dive has no formal performance requirements and is made
prior to completion of all open water training dives. There is
no limit to the number of excursion dives a student may participate in while in training. Excursion dives give enthusiastic student divers an opportunity to go on another dive just for fun. During excursion dives, student divers gain supervised experience by applying general diving skills such as
buoyancy control in the open water environment."
So technically I could keep a diver on excursion dives until they don't bounce off the bottom. Then move on to the next open water dive.