Bounty risk modifier math

Hello im looking for any leads how:

bounty risk modifier work. From now BRM

Fist of all please refrain from obvious answers we all know that it goes up when PEW PEW and down when RAT.

Im and most of the comunity whud realy want to know what math is behind this. Cause its not this simple we just had 75 kills in system in big battle and BRM lowered 2% from 95 to 93. !! YES LOWERED!!.

So can somebody explan what is a driving mechanic about it ? Isk lost / rated ? size of the ships lost ? Its obviousli not numbers of killed ships cause we whud not have this topic.

Im sure every one whud like to know

Its like reputation gains, only the most expencive thing destroyed per “tick” counts.

For example, in the M2 titan brawl, the BRM only went up a few % from the whole battle and didnt even max the system at 180% that day.