Part of the way that Amazon handles ebooks is by location, not by page number. When things change (font, size, spacing, margins) it will change the look, amount of words per page, and so on. If you need to jump to the same location in a book, you should be able to type in the same location number on both.
The same thing can happen with print books. Pages don't always match if each person has different printings (hardcover, paperback, print runs...).
How is it causing a problem (other than just the possibility of a page/screen starting with a different word/paragraph?