Inkjet T520 defaulting off of pc3 when plotting

[PraetorDaemon]

Through AutoCAD, I've been plotting random test prints. In order to make them look ideal, I went into the pc3 prompts to modify the paper margins so they're all 0.67 inches (size necessary for my setup). For whatever reason, when I preview the print, it looks perfectly fine... the margins are all 0.67, the colors are coming through; it's excellent. The second I actually plot it however (without changing a single setting), the margins re-default. After careful examination, it seems that the printer is ignoring the settings I've changed in the .pc3 file, and just defaults to the standard margin. Moreover, I've tried to download the driver to modify it there, but it doesn't recognize my plotter despite the fact it is directly wired into the computer.