by lachlaan » Tue Apr 21, 2015 12:49 am
That was the old system, where clothes and artifact needed to ahve matched proficiencies in order to benefit from the lower difficulty result. Now clothing just has a fixed difficulty it gets crafted with (based on Thread & Needle levels of the crafter) or that it can acquire via some "caressing" with a teasel, I assume also based on the T&N level of the person doing said action.
Artifacts instead count as having a difficulty closer and closer to their lowest one the higher you get in its proficiencies, probably up to some cap. I personally concluded that 150ish in the proficiency was only ~1-2% off from best possible result.
As far as the math involved is concerned, Loftar had put up some complex mathematical probability formula somewhere when the new system was added.
Oh and it's multiplicative, no subtraction involved @ Argentis, although it doesn't vary that much. Would be 67.5% success rate in your example.
Exactly 6.022 x 10^23 worth of Lach molecules.