Originally Posted by Bluedriver

You are confused. Category doesn't mean type. I'm not EXACTLY sure of the precise definition, but it basically means narrow-body or wide-body. It CAN be further broken down into small-narrow-body and large-narrow-body, if the arbitrator thinks it's important, but frankly the A220 and A320 overlap as it is. The A220-300 has the range and capacity of the A319. Airbus at will almost certainly by the time SLI arbitration begins, will have announced the long anticipated A220-500, which will have A320 capacity and range. JB is likely to have an order placed for it by then as well. And our A220-300 pays more than your A320.

An arbitrator breaking narrow-bodies into "small" and "large" is more likely if you were talking B717 vs B757-300s, not an overlapping capacity pair of types that basically pay within the distance between Chevy Chase's butt cheeks of each other.