High level crafting plans drop where?

[yasiru]

Could anyone enlighten me to which acts can drop the higher lvl crafting plans, both BS and jewelry ones, including legendary/set? I keep hearing various reports that they can drop anywhere in inferno, but I also have heard many times they only drop in acts III/IV. So which is correct?

I know they are not easily found but it would be nice to know I'm at least looking in the right places...

[Resentful]

Act 3 and 4 share the same drop rates so in this case OP

Spam act 3