Steady Hand: Additive or Multiplicative?

[OrganizationXIll]

Additive.

Steady + Hasty = 70%, Steady + Basic = 90%, Steady + Standard/advanced = can't fail.

Unless it has been changed since release week, this is not true. (No patch notes mention a change) I had a Standard Touch Fail with Steady Hand. That's 80% + 20%? So, according to you, it didn't happen?

With Steady Hand I:

80% + (80% * 20%) = 96%

With Steady Hand II:

80% + (80% * 30%) = 104%

TL;DR - Multiplicative. Steady Hand II makes most skills over 100% chance, but it isn't added directly on top.