Right, maybe that was a poor example.....
A threshold for .6 on a three character query still searches for 1/3, 2/3 or 3/3 identity.
Similarly, a threshold of .7 on a 5 character search yields 3/5, 4/5 and 5/5 match. I would say I prefer to round it UP, rather than down, as by definition somethin shouldn't be below a threshold. I am just looking for a way to tighten it up.