Saying no to a skip now because you don't want him to ask for another later sounds a bit like panicked thinking. Make the decision for now - anything could happen between now and later.
I totally agree with this, and I wouldn't say no, we are all for the skip, it's just the only "challenge" I anticipate in the future as he is a voracious learner and I would anticipate that it will come up again.
He wouldn't move up to the top, as the school is K-8 so even with a skip he has 3 more years at that school.
