They know what they did wrong with K4 and it wasn't an unknown...

They know what they did wrong with K4 and it wasn't an unknown geological phenomena that could "strike" again. They also managed to execute 6 or 7 other fracs perfectly to plan.
There is fraccing risk of course but the K4 frack issue doesnt mean the risk of the jaws frack goes up because of something that is not understood down hole. IMO

"Corporate level finance and dilution risk sits on top of that". Yes but that is not a play proving risk, which is what everyone wants to mitigate here. That is a risk as to what the shareholder may receive at the end of the day.
If the play is proven to flow at commercial rates then the reward for investors will be determined by how well the management can engineer the development of the project and the financing / dilution / partnerships that comes with it.

My point around COS was that it isn't a linear increase as we get through the drilling process. IMO the COS takes a jump once the horizontal has been drilled and cased. So if we are 30% COS now then it could be 45-50% or more after the horizontal has been drilled and cased successfully, whereas the completion of the entire vertical well probably only added 2-5%.

IMO