Ok, I investigated this further and it seems this is now on one hand a minor cosmetic combat calculator bug and on the other hand some weird calculation that I can't figure out where it comes from...
My mod loads fine and it indeed does have an effect. I ran the game with three different mod configs:
1) Unmodded
2) With the Horem's mod that divides the barb bonuses by 2
3) With my mod that sets the barb bonuses to zero
In each mod config I played the game to capture three different scenarios with my warrior attacking a barbarian brute. The barb was always on open terrain and without any supporting barb units i.e. the barb has no bonuses on his side. The scenarios for my unit were:
a) No promotions, no flanking i.e. supposedly no bonuses.
b) Open terrain promotion +15%, no flanking
c) No promotions, flanking bonus +10%
In every one of the 3*3=9 cases the combat calculator showed in the info screen the standard text for the bonus vs. barbarians and always with the value "+40%". However, the strength values the combat calculator showed did vary between the three different configs! So, I think there's certainly now a bug in the combat calculator that regardless of the actual bonus value the game uses, it still always shows the barbarian bonus as "+40%" even though it's not the true value. So, the bug is only that the info text as a text is wrong and does not react to the barbarian bonus setting although the combat calculator does react to it.
But I still don't quite understand the strength values I got from the combat calculator. The combat calculator showed "8" as the strength of the barbarian brute in all cases which is correct. However, the results for the strength of my warrior were:
Case a: No promotions, no flanking
1a) BarbBonus=+40%: 13.2
2a) BarbBonus=+20%: 11.6
3a) BarbBonus=+0%: 10.0
Case b: Promotion +15%, no flanking
1b) BarbBonus=+40%: 14.4
2b) BarbBonus=+20%: 12.8
3b) BarbBonus=+0%: 11.2
Case c: No promotions, flanking +10%
1c) BarbBonus=+40%: 14.0
2c) BarbBonus=+20%: 12.4
3c) BarbBonus=+0%: 10.8
Now, both the warrior and the brute are strength 8. So, could someone explain me the above numbers from the combat calculator? In the scenario a (no promotions, no flanking) I think that I should have got:
1a) 8+0.4*8 = 11.2
2a) 8+0.2*8 = 9.6
3a) 8+0 = 8
for the three different mod configurations. Similarly, the values from cases b and c should have been:
1b) 8+0.4*8+0.15*8 = 12.4
2b) 8+0.2*8+0.15*8 = 10.8
3b) 8+0*8+0.15*8 = 9.2
1c) 8+0.4*8+0.1*8 = 12.0
2c) 8+0.2*8+0.1*8 = 10.4
3c) 8+0*8+0.1*8 = 8.8
But they weren't. So, what's going on here? Calculating backwards from the results I did got it looks as if there was some invisible +25% bonus modifier in each case. If you assume that such a bonus exists then the results from the combat calculator would indeed all match perfectly i.e.:
1a) 8 + 0.25*8 + 0.4*8 = 13.2
2a) 8 + 0.25*8 + 0.2*8 = 11.6
3a) 8 + 0.25*8 + 0*8 = 10.0
1b) 8 + 0.25*8 + 0.4*8 + 0.15*8 = 14.4
2b) 8 + 0.25*8 + 0.2*8 + 0.15*8 = 12.8
3b) 8 + 0.25*8 + 0*8 + 0.15*8 = 11.2
1c) 8 + 0.25*8 + 0.4*8 + 0.1*8 = 14.0
2c) 8 + 0.25*8 + 0.2*8 + 0.1*8 = 12.4
3c) 8 + 0.25*8 + 0*8 + 0.1*8 = 10.8
As a theory, it explains the results but what is this hidden invisible +25% bonus?? Is it defined somewhere in the game data?