2 wells experience significant cost over-runs, page-74

I am sure you can estimate the possible cost over run.

If the rig cost say a million a day and it took 100 day to drill and the farmin cap = 25 million leave 75 million cost over run and NEN has 25% so the extra to pay is

USD 18 million or so.

No you can fiddle with the daily cost amount and present a range which would be say between

USD 10 to USD 20 million.

Not hard and there no reason NEN did give us a possible low and high ball case.

PS Most daily drilling reports have a column showing the current cost of the well.