I'm having the same problem, but I didn't realize it was related to Yosemite. Figures. :-(
I need to print booklets. From InDesign, I export individual pages as pdf. In Acrobat print dialog, I set size at "Actual Size." But when I click "Booklet," the size CHANGES. In my case, the page size is automatically set too small.
Acrobat Pro XI (11.0.10) -- THIS IS A DISASTER.
The only idea I have at this point is to report this to Adobe as a serious BUG.