Do we need different prn files for different printer models?

I recently pick up the support of the tag printing software for Zebra printers and have a question, hope someone can give me some help!

The printers we have been using are the older type with the model # ZM400 (using parallel interface). Our in-house Software uses the ZPL commands created by Zebra Designer as the template to output (as raw data) to model # ZM400 printer, and it working fine.

Now we brought a new Zebra printer model ZT410 (using USB interface). When we tried to print to it, the output didn’t look right – 2 or 3 fixed text fields were printed with incorrect font sizes! Why? Do I need different set of ZLP commands for different printer models for them to look the same? Another word, do I need to use Zebra Designer to create new ZLP commands sets for the new printer?

Thanks for any help?