I think you brought up good points about the taller cross sectional area.... and together with the higher rolling resistance, and 8lbs more in weight.... I think it would effect the bike. Weight and speed both effect the drag from rolling resistance.
So the S to DS change in city, was about 9%... we can assume that air friction is almost negligible at that point so it's mostly going to be because of the rolling resistance. That rolling resistance increases with speed, so the faster you go the worse it gets (linearly).
Then, the S to DS change in highway was about 15%.... and the main difference being speed. the difference betwen the city and highway change is 6%..... So lets say the Cd*A (Coefficient of air friction times cross sectional area) is most of that, and the rest is because of the rolling resistance.
So I'd say it's close.... I don't see any glaring errors in those values.