Lift and Shift PIA Port length and start digit

I can't find any mention in the documentation about this restriction, but the Lift and Shift will not allow a Port (PIA http/https Ports) that is less than 4 digits or begins with a zero. That is, you cannot use HTTP of 80 and HTTPS of 443. Getting firewall rules in place for different ports will add more time to a very constricted timeline.

Two questions. Most importantly, can we add the 4-digit ports now for the lift and shift/PeopleTools upgrade (8.55 to 8.57) and manually alter them afterwards?

Secondly, what is the reasoning behind this restriction?

Thanks