If your operator defines initial cruise as that to be set in Flight Altitude window, that is your SOP, other operators, .........
After many years and many operators I am still bemused. I've seen many ways of flying the a/c. Generally they conform with basic a/c principles and manufacturer's recommendations, and thus acceptable. Operations of systems is very much the behest of the designers. Why would 'operators' profess to know better and publish SOP's of system operation that are not to manufacturer's philosophy? That has always been a point of suspicion to me. Sometimes it's been OK, and other times not a good idea. That it has been 'approved' has always been a mystery.