Cottonwood
Roadster#433, Model S#S37
OK, that says the regen is counted in the total, but if it is a net total in/out of the battery, regen will tend to cause the total to be smaller than it otherwise would be due to charging losses.
Say you draw 100Wh accelerating the car, then (helped by a slope) manage to regen 100Wh back into the battery: the total will now read zero. However, the battery will no longer be fully charged since it takes more than 100Wh of charging to offset 100Wh of discharge. I don't think anybody has managed to measure it accurately, but there have been estimates in the region of 10's of % loss on the round trip.
Of course, the total amount of regen in a long trip is normally a very small proportion of the energy used - though maybe in city driving it could become significant.
From many observations on a classic P85, 290 Wh per rated miles is the correct number for charging and 300 Wh/rated mile is the correct number for DC charging. If these are correct and the measurements are at the battery, then the difference is only 3.3%. The 10's of percent numbers tend to be for AC to DC or DC to AC conversions.