As a general question to the experts here, does this kind of difference in gauge even really matter? Anchoring on the two somewhat arbitrary numbers above, between 238 seats and 275 it's a 15% difference. Whatever some model predicts is the optimal seat count on a given segment for a given schedule, aren't the error bars vastly greater than 15% anyway?

After all everyone on this forum has experienced the vast fluctuations between oversold flights and empty flights and everything in between, the flexibility of the network to route a passenger a bunch of different ways, and above all the great elasticity of demand, including to shuffle people into more premium seats.

Given that the planning model is still to fix the schedule a couple months in advance based on best guesses and given the relatively blunt instruments available - a handful of imperfect aircraft types with different tradeoffs, a finite number of frequencies that could plausibly be run - is it at all important that a 15% smaller aircraft will be missing from the quiver, compared to the efficiency gains from a simpler fleet and more fuel-efficient aircraft?