O que é Pricing period, price differential?

The pricing period of a physical contract is the set of days whose benchmark assessments are averaged to set its price: for example the five business days around the B/L date (written 2-1-2), or all days of the delivery month. The price differential is the fixed premium or discount added to that average; it carries the value of the grade, location and timing relative to the benchmark, and is what the parties actually negotiate.