It is payable nickel that earns the $5.70 per lb, not the concentrate nickel.
Concentrate nickel is what is delivered from the miner to the refinery. The refinery does it's processing thingy and the output is a quantity of payable nickel. Payable quantities are always less than the concentrate quantities. That is the nature or refining.
Some companies report their metrics as payable quantities and others like WSA report their metrics as concentrate quantities. It can be a trap when doing simple number crunching. That explains why you can't multiply the concentrate number by the average realised price.
