why are my footer page numbers different font sizes

When adding footer page numbers, they come in different font sizes, even though the specs are the same (10 point).

I am adding page numbers to a document but in page ranges. Example: I add "new footer" and insert page numbers 1-4 to pages 5-8 and click ok. Then, I add "new footer" again and add page numbers 5-8 to pages 10-13. There are title pages in the document, and I do not want them numbered. Hence, the page range numbering. The pages are a combination of Excel and PPT files that were converted.

Does it have something to do with the copy on the page or perhaps the margins in the original document? I'm baffled. For some reason, they come in all different point sizes.

Mary Merrill