NPV of a project (which in this case is more or less the same as the company) is essentially a calculation of what the company is worth today by looking at future cash flow and discounting it (money in 10 years is worth less than money tomorrow because of interest, opportunity cost, etc). As you move forward from building to construction the focus is more on how well they are delivering that income from quarter to quarter and year to year, so the focus becomes EPS. There is no golden moment when valuation changes, but it's generally after reaching full production.