This seems a bit of a mystery to me - that's why I had not responded before.
Some printers, including some Lexmarks, have a setting that tells them to skip blank pages, but that should apply to PCL as well as PostScript. Not knowing what printer you have I can't check what it can do, anyway. Maybe you should look through the printer's browser interface and check if there is a "skip blank pages" setting. It's also possible that it's implemented in the PostScript driver, in which case you should find it somewhere in Printing Preferences. In that case the driver setting will override the printer setting, so check the driver first.