it works, but I overdo it by far. I assumed it is % over basic 100%
for example, I have value=50 for corps and 99 for army, my crossbowman when joined in corps have more than 2x strength... It brakes to many things. it should be like 50% more power for corps and maybe up to 100% for army, not more than that, as it make city defenses to weak.
I will put it 25 and 50 for next game, and than we will see...