How many times did the MMPRs become kids?

I just saw the Back in Time series, but I seem to remember another episode.

Don't forget the entire Alien Ranger saga. That featued nothing but MMPR as kids.

There is one minor exception, Billy turned himself back into a teen part way through.

Technically anyone under 18 is still a child in the eyes of the law and adults. So in MMPR at all times they were kids.