Yes, for my class the +-2ft. was mandatory. Also to clarify, my instructor sent me a video of him doing all of the skills and how he wanted them done. He also wanted me to send him videos of me practicing the skills so he could comment on what I was doing right and wrong. Since he was half way around the world from me this gave me a chance to practice before we met in Curacao for the class. He was very shall we say "no nonsense and precise" in a GUE sort of way, which is why I picked him.Wow, so you pretty much removed all tanks, hovered and reattached with a 2ft variance. OK, great challange and I'll practice this for sure. I'm a firm believer in practice and being prepared. So is the 2ft variance the standard?