Thanks for the pics! That is awesome that the PC-Plus models come with the PEQ on the amps. I had no idea that they did. That is one of the things that I really like about my Ultra.
If you have any questions about how to use that, just let me (and the others here) know. I'd be happy to help you out with it. In general, it allows you to flatten out one hump in the frequency response (if you have any). I used a test tone CD and SPL meter and measured the response from 15Hz (or maybe it was 10) up to over 100Hz. I was able to use the port tuning (in conjunction with the subsonic filter setting) and room compensation (which I don't see on your amp) to tame a hump at the lowest end, and then I used the PEQ to tame another hump up around 65Hz. Worked great. I mention it because your sub has almost the same capabilities to get a flatter response, so something to think about.