Premature page break after introduction

I have a case where I am getting a page break after the introduction, but it seems like there is plenty of room to start the chapter:

Another book in this project starts the chapter just fine:

Any thoughts as to what the issue could be?

Actually, I just reduced the size of the \ip font from 0.9 to 0.86, and it was able to put the beginning of the chapter on that page:

It requires a lot of text to be able to start the chapter?! 2.5 paragraphs? Is that adjustable?

I am guessing that it has just crossed the “Page Full Factor” so that it doesn’t start the text on that page. You can override the default by adding this line (setting it to 90%) to the ptxprint-mods.tex file:


Thanks for that. What’s the default PageFullFactor value?