Unless I'm missing something, a spread between 10 and 20 is not a place where you can 'buy for 10 and sell for 20'.
Otherwise these 2 guys could fill their orders immediately.
10 20 means you can sell for 10 and buy for 20 instead.
Otherwise these 2 guys could fill their orders immediately.
10 20 means you can sell for 10 and buy for 20 instead.