Well I've been told by teachers and have read that the top of 10-15% of any class usually could be moved up to the next grade. Those aren't the gifted kids. The top 10-15% do just fine a grade up, working at a similar pace to before but just more demanding material. A gifted kid would need a faster pace (usually) more depth, and maybe 2+ skips. SO they are not distinguishing between those 2 scenarios.