Thanks Charles Kenyon! I had written a long reply to lgambi's #5 before your #6 appeared, but then I pressed "quick reply" and it somehow disappeared, shame. This solution works for me, thanks!

So from what I understand from your answer (and from what I had discovered in the meantime and was writing about...), the size of the margin and of the footer seem to be independently determined, and the text stops where the larger one begins (so that if one of them is larger, it pushes the text beyond the other). Correct? So in lgambi's case the footer was smaller than the margin, and there was still enough room within the margin, so your solution worked, but in my case the footer was already larger than the margin so expanding it pushed the text further up?