I think it takes about 9-10 hours to get the SOC up into the high 90%'s.

Then the charger cycles on and off every few minutes to "balance" and top off the battery, it's not continuous the last couple of hours. So hours is not an accurate way to measure... you really need a meter.

Yeah... if gas is $3.00 and you average 30 MPG... that's $0.10 a mile.
If you can pull out the stops ( in a FEH ) and get 40 MPG, thats still $0.075 per mile. So electricity costs less as long as you get fewer than 75 MPG. Of course you will never get back the price of the batteries at today's prices. But "in theory" 75 MPG is the tipping point.