The author wants a bigger margin at the bottom of a 200-something page book. I am changing the margins on the master pages, with "enable layout adjustment" checked, and it's not affecting the layout in any way. I have also tried clicking on "adjust layout" under the liquid layout box, also to no avail.
I inherited this project from another designer, so am not sure if there are any strange settings I am unaware of
That's only going to work if the text frames are on the margin.
They are on the margins.