ECM and decoys mathematical problem

I've detected a big problem yesterday in the mathematical model of the ECM and Decoys in HCE.
When editing the Battle of Baltim scenario, as I'm not very satisfaced with the very low levels of ECM and decoys, and also I've lowered the SS-N-2a Styx to a probably more realistic 35%, and employed Decoys Level 2 with a value of 40% (as historically in Latakia and Baltim ALL the Styx fired were decoyed with ECM or decoys, and none get his target, and I want to essay that outcome in the game).
Doing that, my prediction was the Styx targeting value will be as a negative -5% (PH=35%, minus ECM or Decoy Value=40%, as result a negative PH=-5%), and it will never hit the target.

But after some tests and variations, the outcome is THE OPOSSITE !!! The Styx EVER get his target!!!

I've obtained with more test consistent results, as in this table:

ECM problem:

SS-N-2a 35% Decoys 40% PH=251%

SS-N-2a 35% Decoys 35% PH=0%

SS-N-2a 40% Decoys 40% PH=0%

SS-N-2a 39% Decoys 40% PH=255%

SS-N-2a 30% Decoys 40% PH=246%

SS-N-2a 40% DECM 45% PH=251%

As consecuence, if the ECM or chaff value is higher than the missile PH, the Game Engine rest the missile PH from 256, and the resulting number, as in the example by far higher than 100% (as 246%), is the very very high PH of a very primitive missile as Styx when the target is defended by advanced ECM !!!!!
I fear this will be embedded in the Game Engine and of not easy solution .... I can only keep very low the ECM and decoys values, and higher the missile PH, to avoid the case ....