2% isn't really much in the world of tire sizes. Considering how non standard tire sizing is, you can find a 2% difference between two tires of the same size between brands. I wouldn't sweat 2% at all.
ya, if you are going 60Mph, it should read 61.2 or 58.8, depending on which side of the coin it is.
If you are doing 60 and cops clocks you are 61, 99.999% will not give you a ticket... if you are doing 70, or 71, fine will be the same.