I bet the GT and GT Performance are why we see a discrepancy. If I had to guess, it's the GT Performance's MagneRide suspension which uses computer sensors and electrical currents to change the shock damping rates at an incredibly high frequency.
And remember that all those figures are based on slow/medium speed driving, not fast (interstate). Even the EPA "highway" figure is based mostly on 55 MPH, not 65 or 75 where BEV efficiency typically drops 25-30%.
Always need to take that into account when estimating how far you can go on a charge. If you're expecting much of it to be at interstate speeds, I'd take at least 50 miles off those figures.