Hey @attah ,
thanks really much for your deep interest in this matter. I don’t know if i can answer all your questions. I am only printing through your sea printer app on a Canon Pixma TS5150 network printer. It was a Hermes packaging label: Version 1.0.2. You can find samples on Google. Like i said, as a postcript document it did not print correctly, but as a picture yes. So my thought, was an error with vector graphics or also the barcode format.
hermes paketschein version 1.0.2 - Google Suche…
Sorry for not being able to be more precise.
Thanks for your hard work for the community 
Greetings