I am a little suspicious of our 27kWh/100mi number. Is that from the actual meter reading to charge the battery or just what OnStar says? The LEAF forums put the charge at 24kWh to get 21kWh into a fully depleted battery. Meaning for the 80mi range you get around 300W/mi (or 30kWh/100mi in your units). If your numbers is accurate then maybe there is a good case for the battery conditioning that the Volt uses.
Even using your efficiency I get a 25% higher cost using my electric rate:
(1427mi * .27kWh/mi * .11$/mi) $42.38 electric + (115/32mpg * 3.8 $/gal) $13.65 gas = $56
Using numbers from the LEAF bloags it comes out only a little cheaper:
1542mi * .3kWh/mi * .11$/kWh = $50
My Prius gets over 48mpg, which puts the cost of 1542mi at $122. While $72 isn't chump change, I don't think a Volt or LEAF are going to beat a Prius in cost over the term of a typical car loan. Energy independence and cleaner air are still going to be my main reasons to be an early adopter...