Exporting PDF won't give inside/outside bleed?

Hi everyone,

I'm preparing a zine for print. In the doc setup, I have my inside and outside bleeds set to 0.25in:

However, when I go to export the pdf to send to our printer, left/right bleeds my only option- no inside/outside.

This still happens when I check the "use document bleed settings" box. I have no idea what is going on. I have CS6 for Mac.

Any ideas for how to troubleshoot this?