I assume that you have had the front end alignment checked. If you have then the tire guy is probably right.
A lot depends on how well your toad tracks behind the coach and especially how it tracks during a tight turn. Some toads track fine and some tend to scrub the tires on a tight turn.
Remember when you make a tight turn the rear end of the coach is swinging out and causes the toad to do things a little different than just following in the tracks of your coach. This will increase front tire wear.
All you have to do is have someone do a tight turn with your coach while you watch what happens to your toad. You will see that it does not track right behind your coach but follows a different path.