I think Chris could be right about slippage but the thing that has me stumped is that your dec graph is excellent. I would think that if it were slippage or polar alignment dec guiding would be all over the place.
I guess if you double check everything to eliminate from the equation what isn't causing the problem you'll be left with the thing that is.
Definitely do some PEC training on your mount. The less guiding phd has to do the better. With a low pe and good polar alignment only minor corrections are needed from PHD.
Try changing you min motion to something ridiculous like one second. At the moment with 0.05 phd is only issuing a pulse command for 0.05 of a second for every correction phd issues, and if your guide exposure is about 2 secs your RA motors only receive a correction of 0.05 seconds every 2 secs. If you increase that 1.00 and see if if phd can move the RA line above the centre line then work backwards from 1.00 until the RA graph settles off.
Read this,
http://www.rosecityastronomers.org/r...eToGuiding.pdf
It explains what all the setting in phd do, it helped me a lot.