I doubt it will. 4.5 to 5.5 really isn't significant because 5 is a pretty rare occuring point differential. There may be some 6s out there but I haven't seen any 6.5s. But if you can get 7, you might as well go for the middle. Don't get many opportunities like that.
At 6.5 or higher, I think the value is definitely gone on TB.