style:page-usage="right" on a single layout is a page that starts on the right,
not one half of a book, and swapping its pair drew it 9mm off. It counts as
mirrored now only where masterPageHF found the twin it alternates with. The
even-page shift is per section and per first/rest page too — a cover or an index
between mirrored pages has margins of its own and mirrors nothing.
Steffen Becker
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