can't have a grade based model with a 5/1 or 6/1 limit, those kids would be in a grade above the others.[/quote]

Depends on where they started school. For example, there are quite a few kids born in the summer of 2001 that are going into 8th grade (for the first time) and have never held back. Same for other grad years - the 5/1 or 6/1 cut off date would allow these kids but would filter out the hold backs. It level sets the grade based model without letting clubs manipulate the system because there is an age based requirement too. USLax proposal of going age based by one year increments is not going to garner much support as the grade based train has left the station but many grade based supporters would get on board if they suggest the grade with an age element.