At Airbnb documentation, "payout rule" or "payout route" is a concept related to splitting funds from a reservation into different payout methods and persons.
The concept of "payout route" is not the same as "payout method" or "default payout method" on Airbnb documentation.
Maybe documentation is wrong. Maybe the development team has modeled this detail different from the documentation.
The Advice that
"When you add a new payout routing rule, it will apply only to new bookings that are confirmed after the rules were changed, not to reservations that have already been confirmed."
Is not present under the title where they explain the default payout method.
Several payout methods are not referenced as "payout routes" or "payout rules" on the documentation.
So it has sense that if you have set a special splitting routing rule , keeping memory of that splitting on every reservation made.
But for money whose destination payout was set as the DEFAUT payout method, they should just keep this DEFAULT placeholder on their memory, but not the content of the placeholder.
When you change the DEFAULT meaning, payouts on hold for the previous DEFAULT should now be assigned to the new DEFAULT value .
One thing is to hardcode a special payout method or routing for some listing, some reservations.
Other thing is to use the placeholder DEFAULT as the payout method for listings.
Completed reservations which used the DEFAULT placeholder to define the payout should only retain the DEFAULT concept while they are on hold at Airbnb by the minimum payout value or any other delay, to allow the user to modify the content of the DEFAULT and redirect the hold funds where the user wants the payout to be done now.
This aspect of payout is under documented. And I think its counter intuitively modeled. Airbnb should fix this.