Except the Pro S also comes with 19" wheels, it is the Gradient package that gives you the 20" wheel. It does seem like the Pro S does get a different tire that the Pro, though. I seem to recall that all Pro S wheels in the US are Bridgestones and the Pro wheels are Hankook Kinergy, so that could make a difference. I'm curious if VW tested the Pro S with the Gradient package and what actual difference there is in the 19" vs. 20" wheels on the Pro S models (both RWD and AWD).VW also says the AWD Pro is 9 miles more range:
The EPA-estimated range is 249 miles for the AWD Pro and 240 miles for the AWD Pro S (Statement).
Which nearly matches the 10 mile difference for the RWD pro versus pro S, likely due to the 19" wheels and maybe better tires.