PE of 30...ouch. I'd be looking at getting that down with pec training before I did anything, but I don't think that that is your issue.
Have you ever had good guiding with this mount? When I got my G11 my PE was around 25 and I couldn't guide the errors out. I needed the worm replaced.
Here is a few things to try.
Download the trial version of Pempro from ccdware and verify that your polar alignment is good. 15 secs subs before trailing suggests to me that your polar alignment is out by a lot. The PE of 30 could account for that but I don't think it would make your graph trail off like that. There is a way to use phd to drift align, at the very least I'd try that.
http://njstargazer.org/PolarAlignment.asp
Run the pe training module in pem pro and see how much pe you can correct with training. It's an excellent piece of software.
Increase your aggression settings in phd.
Post your settings in phd
Cheers