Originally Posted by
framer
Is there an Engineering disadvantage to how we do it? Ie cycles of Pressurization weakening the fuselage?
That is indeed why the recommendation is to set highest expected flight level pre-flight. The re-selection of the Altitude Selector in-flight can cause
a change in maximum differential which is an unwanted event at cruise levels. This change in pressure differential can be prevented by selecting the highest expected cruise level pre-flight.