My systems jump around when I insert pages

I have carefully managed to get many systems fit in a score with the wanted staff size. The percentage at the bottom is 110. When I insert new pages before page 1, the systems jump back to some default places and do not fit anymore. Is there a way to get around this and lock the systems so I don’t have to fix everything again?

Welcome to the forum Per - if you moved staves around using the square handles in Engrave mode, unfortunately those offsets get lost if the page number they originally occurred on changes (see the note here).

Do you want to share your project here, as it might well be that adjusting the per-layout vertical spacing options in Layout Options might get you close to your desired result without too many manual changes?

Thank you, Lillie!
That helped a great deal.