As you can see, the numbers vary quite a lot. Even with the same driver. But, I did learn something today. The EPA came up with the numbers that figures out the MPGe, and it's 33.705 (equals 1 gallon of fuel) x Avg mi/kWh (see https://www.inchcalculator.com/convert/mile-per-kilowatt-hour-to-mile-per-gallon-equivalent/ ). So long as your average mi/kWh is at least 3.8, you are doing slightly better than the EPAs estimate on the 2020 Bolt (127/108). On my 2020 Bolt Premier, I have seen a low of 3.6 (city only). So, that was lower than the EPA estimate, 121.3 MPGe. But, I have also been as high as 6.1 (currently 5.1; city only). Now, I'm doing far better than the EPA estimate; ranging from 151.6 MPGe to 252.7 MPGe, with an avg of 171.8 MPGe (though, I have seen an avg of 205.6 MPGe).
I got 4.4m/KwH on my last big trip in Sept. 2021; Philadelphia/Lake George, NY; Montreal QC, and return. I drove 1,100 miles in 11 days, 3 adults + luggage in the car. I did not try any hyper mileing tricks, and used the A/C when warm. I was very satisfied. I only had to pay for electricity once, at the EVolveNY fast charger in LaGrangeville, NY, just over $9.00, for almost 24 Kw. All other charges were free.