Managed payments fee question

[valleytradeshop2012]

I know this gets beat to death, but I am still finding that some of the fees being charged are not making sense. I sold an item today that was listed in the collectibles/advertising/retail/drug stores category. It was listed with one of my free listings. It was a buy it now listing and it sold for $3 with free shipping. The buyer paid $3.24 total with tax. I was charged $0.70 in fees and wound up with $2.30 in my account. If this category has a final value fee of 12.35% plus the $0.30 per transaction, my math shows I should have wound up with more than $2.30.... What am I missing?