Windows 1.0.5 - inconsistent experience gains from divination candle battles

The experience my monsters got from divination candle battles for two different creatures appears to be inconsistent. Example:

Helios battles gave 4.50M exp
Bile Abomination battles game 12.50M exp

around a 3x increase for some reason from the same task, I have C knowledge in Helios and S knowledge in Bile Abomination

Your experience amount goes up at B knowledge.