the circadian “window” doesn’t belong to the pairing, it belongs to the pilot operating that pairing. If a pilot has been operating this type of pairing all month long, he/she has had time to adjust. If any pilot who operates this pairing is used to being awake during the day and sleeping at night prior to starting this pairing, it is outside of their window/rhythm. It can take a normal person over a month to fully adjust from day walker to night walker.