Ed...your time sounds about right to me. Last time I did a 6# turkey breast it was about 5 hours, and you definitely want 165IT before pulling it. In an earlier attempt last year, I thought the breast was done prior to 165IT (it seemed like it was taking too long!) and it was a bit mushy in the center of the breast meat. Now, I just budget 5 hours, with a little wiggle time built in!