If I am understanding your question, I would imagine that many parents feel comfortable home schooling when their children are younger but not when they get into the higher grades. Coupled with the fact that it's very tiring to home school for long periods of time. So I think many children that were home schooled when they are young are put back into the public school when they get older. Also many parents want their children to get an actual high school diploma. So they put the kids back into public school sometime when the kids reach high school. We may do the same. Haven't given it enough thought yet.

Hope that answers your question.