CONCLUSION: Fire at Will is using player and equipment Accuracy boosts when calculating its chance to hit.
So... where does that leave us?
Great test, simple and informative. However, just to cover all the bases, I would repeat the same test vs. 2 NPC's, then 3, then 4, etc. just to look for consistency (just in case BFAW behaves differently vs. 1 or multiple targets). Assuming that checks out, then I would investigate the following:
An error in the reporting of hits/misses
1. parse manually and see if the "accuracy bug" shows up.
- If it does, then the error is in the delivery of hit/miss information by the game.
- If it does not, then the error is in the delivery or interpretation of information by the parsing programs.
I would not proceed to speculate until I knew the above outcomes.