Anyone else finding the difficulty in Forza 6 quite inconsistent?

I'm playing on the difficulty which gives 35% payout, and some races I will be leading by lap 3/5, while in others 1st place will be miles ahead by the end of lap 2. In some if I am leading I will steadily increase my lead until I cannot see 2nd place on my map, and in others in the final lap the car behind me will suddenly up the difficulty and seemingly shift up to a new gear.

Anyone else finding this? The game is far too easy but far too hard at the same time :P

This aside, absolutely love this game :)