How did jerry get $11 and Elaine $9?

Elaine: I’ve put up an order to sell 1 Seinfeld contract for $10

Jerry: Now I’ve got [...] 1 Seinfled

Elaine: I’ve got -1 Seinfeld, what does that even mean?

Jerry: It means Elaine, you need what I have

Elaine: Hah! But you also need someone to buy that 1 Seinfeld off you if want your money freed up again

Elaine: It says the contract is valued at $100 worth of Seinfeld

Jerry: I’ll put my order at $10.1

Elaine: I’ll buy it back at $10.1

Jerry: Now we both have 0 Seinfeld, I have $11 and you have $9

What’s happening here [...] The protocol parses the index# of the contract that is being netted to 0 and compares the price of that transaction to the price of the contract that nets out the first contract. In this case, both parties in a transaction are netting positions. The price difference between netted contract is a positive number, so a settlement will be paid to the address that is reducing a positive balance by 1.