Sorry if I missed this discussion, but what's the rationale for US to keep their A320s at exactly 150 seats, meaning the addition of a 3rd cabin crew member?

If I were a smart Dougie, I'd hardblock one of the seats to make it 149 and save myself the extra salary cost.

Since Dougie is a cost-cutter, I'm surprised that a) he hadn't considered this, or b) the extra revenue from just that one extra seat justifies paying another FA.

Or am I missing something?

Thanks.