Oh come on...
We know nothing of the sort. It appears Rossi told Bass that he was cooking platinum sponges, but Bass clearly has no clue what is going on (if anything) at the facility and is simply asking Rossi what he is supposed to say.
And the invoice for nickel powder was just a camouflaged payment for tax preparation fees incurred by JM that Rossi didn't want it to be known that he was paying for (read the email - there was no nickel powder).
Pure theater.
Most likely is that there is absolutely nothing going on there...