Purge--
The "page numbers" on ePubs don't refer to the number of screen changes as the LRFs do. They refer to specific locations in the document. (That's what Wallcraft is referring to.) No matter what size of text you choose, the "page numbers" of ePub files will stay the same. If you're using a large font, it could well take four or five "page turns" on an ePub document for the page to change. A lot of the ePub books I read require two to three page turns before the page number changes--even on the small font.
dordale