what am i doing wrong?

You just need to work with the car to whittle down the ETs. Raise your launch RPM, raise your shift points a little at a time and see what happens. When you slow down, back up.

My first run with my car was a 15.991 @ 87.70 MPH with a 2.595 60'.

Now it runs 12.217 @ 111.04 with a 1.829 60'. Granted, I changed the motor (went from a 318 to a 360), but I also made signifigant improvements by making changes to my driving style.