Perplexing Booklet Problem
I am creating a 1/2 fold brochure on 8.5x11 paper. I've attached a screenshot of the Properties panel. My document is a multiple of 4. 12 pages divided by 4 equals 3 sheets of paper. When I attempt to export the PostScript file, InDesign tells me that 2 blank pages have been added to create the booklet. All pages contain text and/or graphics.

I create booklets on 11x17 paper all the time and have never had this issue. What step have I missed in my document set up?
