Why is "append measures" no longer really an "append MEASURES" command?

When I append 20 measures, it doesn't really append 20 MEASURES. What it does instead is, add ONE 20 measure REST at the end of the score. The reason I want MEASURES instead of a REST, is because I want to put notes in these measures. Not because I want to add a 20 measure rest, then delete that rest (which I can't figure out how to do by the way) and then add notes to particular measures.