Is My Lifetime MPG Actually Higher Due to 199.9 EV MPG?

Regen isn't the same; that energy has already been expended getting the car up to speed, so it's "free" in the sense it was already accounted for and you're just getting some of it back. However, the displayed MPG is also not accounting for the energy added to the battery from a charger, which is not "free." To get a true MPGe number, you would need to convert the KWh charged into gallon-equivalents at 33.7 KWh/gallon, then add that number to actual gallons of gas used and divide into miles traveled.