Upgrade Station Ship's Hull bug?

[Goty]

So in the upgrade station you can reduce the ship's hull failing % (the first icon), it says the default chance is 20% and reduces by 2% per level, so the max level should be 10 (20*2 = 20%), but i have level 12 (2*12=24%) and i'm still getting failed expeditions so:
A. there's something WRONG there.
or
B. it's not explained correctly?

Thanks for helping

[erebs]

its 2% of 20 which is 20.4 after upgrade

[ExWhiteWolf]

max level is 50 at 0.4% reduction per upgrade

[Goty]

Thanks =D