I would suggest that you abandon the one-tenth trials and instead move to three-tenths or 0.3 grains. It's been my experience that if you don't try to create a genuine, noticeable change, all the testing gets lost in a blur.
Your Lee PPM sounds like it's working well for you -- good deal, and Power Pistol helps in that regard as it's a darn good metering powder. But again, keep in mind that even some of the BEST powder measures on their best days will simply give you charge weights that can vary ever so slightly -- such as 0.1 grain. This is another reason to move to something like 0.3 or 0.4 for your stages.
Keep up the good work.
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.