InDesign Booklet Printing Front and Back Pages Different Sizes When Scaling (85%) on Home Printer

I’m trying to print a project as a booklet on InDesign. I’ve printed a few before that were successful (after some troubleshooting), but I’m currently having an issue I haven’t run into before:

When I test print the first four pages of my file to make sure the front and back are aligned, the front of what’s printed on the page is about 1/8” longer than the back. The front spread is 10” long and the back spread is 10 1/8” long. 

In the InDesign file, the spreads are 12x9.5 inches, but I’m printing at 85% scale, so maybe that’s the issue? However, 100% scale is too big for my printer (I created the file before I realized I would be printing at home). I’ve also printed previous projects at different scales and it went fine, so not sure why it would stop working now.

The creep is set to 0 inches.

Any idea what could be causing this?

P.S. I’d rather not print from Acrobat. I was having major margin issues and could not get the pages to line up for the life of me (and yes, I adjusted the print position on my printer--that was not the issue). Since I’ve printed booklets successfully from InDesign before, I’d like to try to make it work again. If that’s the only option, though, I understand……...