Yeah, I don't think it's very helpful. It's just showing there are 9 or more seats available in coach. It's not cumulative. Each letter is just a different fare class for coach. The letters showing 4 seats are most likely business class. If so, then there are only 4 seats available for sale in business. A 9 would indicate 9 or more. My guess is that I class showing 0 is some kind of discounted business class that may be rarely used.