I have not bought a pair yet, but have tried them on several times in the past weeks preparing to buy some.
They seem a bit tighter to me than the fit of the Benton. That being said however I wear a 9D in AE, in Alden and in Polo MacKay (EG) and the Polo Benton (C&J??.)
It does seem the last the Tellman is made on is a bit tighter but still within the same sizing width and length parameters. Just maybe a bit thinner across the laces.
You only would subtract a 1/2 size if you were buying them in UK sizing.