When Packing Partner prints, it creates a page that is the correct length on the PC. Some printers interpret this information incorrectly and don't print exactly the same length page.
There are two things that you can try:
You can change the bottom margin to allow for this discrepency from Tools>Options>Print>List margins>Bottom
Turn off font substitution in the printer driver.
In the print dialog select click properties, then find the advanced settings, this is different for each printer so you will need to find it. Then change the Truetype Font option as below: