Hoosiers go away so quick and you may be buying tires that are in their "golden years".
You could email him and ask him the age of the tires, or how many heat cycles are on the tires. Generally after a year or so, or 16 or so cycles, they start going away (ie. performance drops).
A closeup pic would be helpful to check the wear. Also ask if there are any flat spots or cording.
If you figure the cost of shipping and the cost of having them mounted, and your buying price, it adds up. Could be better off putting those funds towards new Kumhos (which perform nearly as well and last much longer).