I tend to trust the numbers, but be sure the numbers are corresponding to the same proxy reference point on all the pages. You might also want to switch to fit spread as the view, then change pages from the pages panel or the page navigation dropdown in the lower left corner rather than scrolling to check for movement.
Thanks for your answer! The reference point is indeed the same on all the pages, and I was using the pages panel to switch between the pages (I formulated that wrong in my original question).
I have put the logo up on a master now, and created 3 masters for the 3 colours. This seems so work better, it is not 'hopping' now anymore.
Still, I find it weird that when I copy the 'normal' page, the logo seems to be slightly in a different location...
You can get that hopping sensation if the page view is different from page to page. The only way I know to be sure the page is in the same position is to use fit page or fit spread on each page.
Ah, now I fully understand you. My bad, didn't read right.
And yes: that is working! Thanks so much!