[Closed] Same size, different results

[TravelingTartar]

Was not sure what title to use to describe this issue.
One illustrator file. Two pages. Each is the same size. I export both to individual PDF files. As PDF files, they have the same size. I have then created a batch to create alternate versions (gif, png, etc.) and different sizes. The problem comes when scaling. If I scale to a specific pixel width, both images come out at that width, e.g. 1920 pixels wide. However, if instead of scaling to a pixel size I scale using a percentage, e.g. 50%, then the two identical source files come out at different sizes (different pixel count) by about a 20% difference. So one comes out ±5000 pixels whereas the other identically sized one, once resized, comes out at ±6000 pixels.
Any thoughts whatsoever on where I might want to look for the problem?
Thx.

[forum_adm]

Please check the PDF import options.
What did you select?
The selection changes the imported pixel size during the rasterizing process.