DCF - Confirmed Cost of Extraction/Production, page-2

Cost of production, or AISC as reported by gold companies will vary over time, and it will take a few months to get an idea of whether
they align to the DFS, the plant needs to ramp up slowly to full production. It's not like coke, with the COGS relatively known, predictable and fixed. It's not 100% steady state output from day one.

DNC have done a lot of grade control drilling, so one would hope there are no surprises.

That is part of the risk of buying a gold developer, you can't really know for sure what future performance will be. Once they have a few months (&years) production numbers the de-risking happens and hopefully, its good news and the SP goes up!