Biasing works both ways. Set the cells, say, 60 across and see if your AFR bumps up ~0.8 across the board. Not sure if the DME limits for rich/lean conditions are different before intervention, but its worth a try. I would NOT set it any more than 10 points either way in the bias map, but worth a try. If it does enlean the AFRs by ~0.8ish after a couple pulls, then its definately your flash likely being set up for gas. Althoguh IMO it sounds like it already, but if you want to put a nail in the coffin.
Edit: before doing any of the above, post of log with fuel correction so we can see that the procede is actually applying no bias at all. I'll never reccomend intentionally going lean (0.8 above 11 is acceptable) but for any other people who find this post and think its acceptable, its generally not.