Matthew P Jones wrote:
The pricing of tickets out to Amersham follows the LU zonal
structure, I would suggest the prices of tickets out to Wycombe are
not comparable, they seem more expensive to me!

Absolutely. It was only about fifteen years ago that the Aylesbury to
Marylebone fare was standardised for both routes. Prior to that, tickets
between Aylesbury and Marylebone via Wycombe were dearer than via Amersham
(although, IIRC, monthly or longer seasons were accepted on both routes).