[aerohead]

1) The combined mpg-e of a vehicle is decided over 11.007-km, 1180-seconds, at an average 33.6-km/h ( 20.87-mph ).
2) This value is extremely weighted towards the low-speed end of the velocity spectrum, where aerodynamics pales in comparison to inertial and rolling resistance fractions.
3) As regenerative braking energy recovery potential, as of 2015, equaled up to 250% battery capacity, and city center bans on carbon-dioxide emissions were looming ahead, it's very likely that optimizing low-speed efficiency of hybrid, plug-in hybrid, and ultimately BEV regenerative braking became a driver for optimizing vehicle mass, as, with a non-negotiable testing regimen, increasing 'available wheel power' was the only variable left on the table.
4) Fort-three years ago I was required to perform multi-variate, iterative, solutions in FORTRAN, which would, could, home in on an 'optimum' parameter, while simultaneously respecting potential ill-effects attributed to all other variables in the ensemble.
5) There's a very high probability that, in today's world of neural-network, software-driven engineering tools, and high-capacity computing capability that, it's relatively straightforward to solve for such optimizations.
6) The original 2012 Volvo V40 was 1463-kg.
7) The 2015 V40 hybrid was 1572-kg.
8) The 2018 XC40 T5 AWD hybrid was 1723.6-kg.
9) The 2021 XC40 P8 AWD Recharge BEV, 2165-kg.
10) I believe that 'legacy' dynamics constitutes a false dichotomy with respect to hybrid, plug-in hybrid, and BEV dynamics, and erroneous conclusions may be drawn if the 'strange behavior' of this subset of the vehicle population is not respected within its contextual framework.