I don't think there is any evidence to support the statement that allocate seating slowed turn.
EI-BUD, Please read my post carefully. I never said it did.
I said, as an example McCall has used when talking about this, that IF allocated seating slowed turnaround times then they wouldn't be doing it because it would harm the low-cost model.
The fact that they ran the trial and successfully do use allocated seating means that as you say, it hasn't had any significant impact on turnaround times.