Right, here it is. It's really long, so only read once you have 20-30 minutes spare, to actually understand what's going on. I basically break down the standard rotation and find the breaking point for it. That breaking point is "sort of" achievable, at which point we need another skill to fill the spot, or fracture.

https://docs.google.com/file/d/0BxbE...5PUm1JYVU/edit

tl;dr, At 630 SS (or 485 SS + Fey Light), which is also 2.2222r Skill Speed according to Purostriders research, we now fit in 9 skills in the space of what we would've fit in 8, thus making us clip our dots if we continue our standard rotation. Introducing Fracture somewhere once we're at 2.2222r GDC fixes it entirely, and gives us a much bigger DPS bosst.

tl;dr;tl;dr, 8WS/20S = no fracture. 9WS/20S = yes fracture.