XYZ Co$.$ has a contract to sell $50$ backpacks to a customer for $$800($$$16$ per backpack$)$ over a six$-$month period. After $30$ backpacks have been delivered, XYZ agrees to modify the contract by promising to deliver $20$ additional backpacks of the same type for $$180,$ or $$12$ per backpack $($which is the standalone selling price of the products for XYZ at the time of the contract modification$).$

$1)$ XYZ wants to consider the modification as part of the original contract rather than a separate contract. Where in the Codification can this treatment be justified?

$2)$ Where in the Codification does it indicate the correct amount of revenue for XYZ to recognize for the next $20$ backpacks sold to the customer? How much will it be$?$