I'm just guessing, but I would assume that since there are distinct Special Meal quality differences between First and Business, that when you plug in the code for say, Veggie, the system knows by your booking class if it is to order up an F or a C Veggie.

So if you put in the code for Obento, and your booking class was Y, it might bounce back an error to the operator, as there is no Obento/Y pairing in the system?

You could give it a try though.