You could try dropping it to see if you get any benefit out of it, but I agree with BBB on this one. You're hooking with 12lbs quite well, as you make more power you may need to drop it some, but depends on the car, suspension setup, etc.
Since that's a 26" tire it won't wallow too much, but you'd feel some..

And Scott.. it's called DRIVING man!
Ask Ghost727 about my 5.6x pass @ Sunshine.. interesting was an understatement...