AH Formatter / XSL Formatter
Q&A

You can force the last page in fo:page-sequence to be an even-page by specifying force-page-count="end-on-even" for the fo:page-sequence. When the final page is an odd-page, the additional page is put on the end of the sequence.

e.g. <fo:page-sequence master-reference="main" force-page-count="end-on-even">