.31 does sound a bit high. (Unless you are using nicads.)
The best way to set safety fallback is to see what fall back you get under normal conditions when temp charging and then set it about 50% higher. So if normal fallback was about 0.08 you would set the safety delta to 0.12. I wouldn't go less than about 0.06 though for a safety delta.
The exception to this is if you are using the charger at low ambient temperatures (below 10 degrees C.) in which case the delta should be set a little higher to prevent false peaking.