I think the PFICO score is a good gauge to know where your Classic it. My PFICO is now slightly higher again. The difference has been pretty consistent when I limit the number of accounts and balances on my CR. Usually runs just a bit higher for me. There are some differences that will cause PFICO to drop that doesn't seem to affect Classic. I think the PFICO score is very important if some lenders are using it. After identifying key things that drop my PFICO not seen on Classic FICO it makes total sense now why WaMu was denying me when my Classic was high, PFICO was not and they use PFICO scoring. For the most part the 2 scoring models work the same with a few differences that usually affect things short term. I would recommend that people use both Classic and PFICO too if applying for credit cards. Just some simple things I suspect but have not proven, like carrying revolving balances for too long or lump sum pay offs seemed to ding my score for 30 days until a new bal and last payment updated. The testing was very limited so I am limiting that to just a guess. But my activity was generating mood swings on PFICO many times each for similar action and Classic didn't care. My PFICO have been dropping and rebounding all year. I say totally worth getting a WaMu card just for the PFICO. And since I found out that my score (besides these score affecting factors) follows my Classic closely, very closely so I have a very close idea where my TU Classic score range is. 
Usually with in 10 points either direction, but when all accounts are PIF generally PFICO will be higher than my Classic.
Usually with in 10 points either direction, but when all accounts are PIF generally PFICO will be higher than my Classic.