"I mentioned in my post that it all hinges on the assays...

"I mentioned in my post that it all hinges on the assays replicating the extraction values"

The extraction values can also be subject to error in the same way that an assay can be.

I once went through and estimated the grade for myself using the density of gold, the diameter of the buttons (as I read them against the mm scales in the photos) and the claimed original weight of the samples used to recover the buttons from to see if the results came out in the right order of maginitude. Assuming that the buttons are mostly gold my caculations confirmed the rough grades but this is by no means a confirmation of the extraction process as I was just using the information provided in the announcements.Esh