I think that my perspective is driven by two or three things: 1) at the point dd skipped (last yr of elementary), we were getting close enough to the point where it "mattered" that we weren't willing to risk having her be placed at a point where she was not going to be a top student, 2) my dd has processing speed issues that make placing her at the level she can work a challenge b/c she probably could not have handled any more quantity and higher level is coupled with quantity at least where I live, and 3) no, I don't think that I'd place a child at the highest level s/he could work in all subjects.
The main reason I say the last piece is that, for us, the point of the skip was not to push her to her fullest extent but rather to have her need to work some so we didn't wind up with a kid who graduated high school thinking that all she needed to do was grace the school system with her presence to get straight As. We wanted her to have to work some in some area and, for her, that area of learning to work was by getting her into one class (her weakest area) where she was accelerated as much as she needed to be and would need to work to get an A some years and b/c the quantity itself developed work ethic.
