Regarding FE,
In the city with slow traffic, red lights and speeds up to 40 km/h the FE is down by about 0.5 km/l. Have also noticed slightly slower acceleration (negligible) but only up to this 40 km/h, 2nd gear range.
Beyond this speed, FE and acceleration are same as before in the city and on highways. So yes, slightly down in FE in the city and on slower speeds only but not by much.
However, the added cushion of the higher profile has increased the ride comfort to a new level. The Bluearth GT tyres also weigh less than the A460 and have a better FE rating.