Oversizing is usually referred to as a wider tread. Need to check the tire ratio with a tire caculator like on Americas Tire website.
Tire Dimensions Made Simple - Discount Tire
Yes, the tire sizes I am running drop the front side wall profile from a 40 to a 35. Which using the tire calculator as a comparision from stock and the 265 & 285's have the best ratio to be similiar to stock as compared to other tire sizes.