Steady Hand: Additive or Multiplicative?

[Teykos]

I believe it is additive, myself, however I do recall a specific window between updates where Steady Hand + Standard Touch did fail occasionally.

I remember this well because someone had just posed a question to me asking if Steady Hand was 10% or 20% and I told them 20% because I had never had this particular combination fail on me and I had been using it a great deal in a macro of mine. With hundreds of macroed trials I felt pretty confident of that. One day I logged in, started crafting with that macro, and things started to blow up on occasion. The first time I dismissed as a fluke, but it happened to me a small handful of times that day. Once the next update hit, though, it never happened again.

I don't think people who remember Steady Hands + Standard Touch failing are wrong, but are instead victim of a bug that crept in and out under the radar.

I'm pretty sure this was either Phase 2 or Phase 3.