My print preview page shows equal page borders around both sides of a
2-page-per-sheet document (A4) but when printed on my new HP Officejet Pro
K550 the left border is closer to the page edge than the right - in other
words the whole 'booklet style' document is off centre and does not fold in
half equally. This only applies to duplex printing - and happens on both
sides! A normal single A4 page with a border and equal margins prints
centrally. My old Epson C62 had no trouble printing this (albeit without
the duplex facility).