We may have talked about this in past years, but how does one arrive at the price of the Sulphur (S) in spreadable AMS = 21-0-0-24S?

I realize there is 420# of N and 480# of S in a ton of AMS, but where do we get a price for strictly Sulphur in the AMS product?

It would be nice to know the cost of the Sulphur so as to compare the N cost in AMS vs N cost in UAN or NH3.

As an example, let's say $400/T for the AMS product.

Thanks