If you are really trying to figure out your BIS you also need to:

1. Even if you made EXP, many of the flights might have been "500 mile" segments where you may have flown as few as 36 miles (SNA-LAX). So just taking 1/2 (or whatever) to reduce the bonus isn't sufficient.

2. You will want to add your award flights. Those are BIS miles (if you are really trying to say "I have flown xxx BIS miles").