Extend charge permission expiration
Amazon Pay's Charge Permission usually expires after 180 days.
However, if you set below parameter in Amazon Pay button rendering script, you can extend the expiration to 13 months. Please use this parameter as needed.
paymentDetails.extendExpiration = true
If you don't set this parameter when button rendering, you cannot over-charge.
As explained in Basics - Object - Charge, Charge expires after 30days.
In case shipping/settlement is scheduled 30days after the order placement, Charge created at time of order will be expired and you cannot capture this charge even if you are ready to settle.
On the other hand, Charge Permission is still open (chargeable), so you can create new Charge against this Charge Permission, and capture it.
Our recommendation is you create new Charge on 20 to 30 days before scheduled settlement day.
i.e. First Charge created on Sept 1 2022, and ready to ship the order on Nov 1 2022.
Charge created on Sept 1 will be expired and you cannot capture this charge in November. However, Charge Permission is still open (chargeable), so you create new Charge against Charge Permission when you are ready to ship and settle in 20 to 30days. Please note you don't need to create Charge at every month just because previous Charge expires. You only need to create Charge at the timing as explained above.
Ref: FAQ - What can I do if I have reservation orders with shipping lead-time longer than 180 days?.