You must mean push the school time forward? pushing it back would just mean they spend more time in darkness.

I'm being needlessly pedantic (sorry) but "back" and "forward" in time is a confusing concept best thought of in terms to "traveling back in time" (decrement your clock, move to an earlier time) "traveling forward in time" (increment your clock, move to a later time).

Saying "push back" is a very confusing phrase to me because I don't actually know what you mean and need to pick it up from context clues which are not always right.