I would add to the above example that with a 3-day delay activation, flights will be booked as-they-come, 72 hours from the activation time.
So at 4.39 flights departing between 4.39 and 5.09 in 72 hours will be booked, at 5.09 flights departing between 5.09 and 5.39 in 72 hours will be booked, etc. until the whole 72-hour cycle is complete. If your first flight departs at 7.15, for example, and you activate with 72-hour delay at 4.05, ORS update runs at 4.09 but the flight won't be booked until 7.09 ORS update time (so 4.09, 4.39, 5.09, 5.39, 6.09 and 6.39 ORS updates will pass without any flight being booked).
With immediate activation, given the example above, at 4.39 all flights departing between 4.39 between 24 and 72 hours will be booked, but not beyond 72 hours and no less than 24 hours.
So today is Friday, at 4.39 with immediate activation, will book all flights between 4.39 Saturday and 4.39 Monday. Then, at 5.09, will be booked flights that depart between 5.09 and 5.39 in 72hours (because everything else >72 hours is already booked into ORS). This cycle then continues with booking flights 72 hours in advance of the current ORS booking time and the next ORS booking time. (This will be same for bot immediate and 72-hour activation).
Also one note - immediate activation is actually 24 hour activation.
Summary:
Immediate activation: Next ORS update will book flights departing 24 hours from ORS update time till 72 hours from ORS update time.
Each subsequent ORS update books flights departing in 72 hours in the future between the given ORS update time and next ORS update time.
72-hour activation: First flight that will get booked is the flight departing in 72 hours between the current ORS update time and the next ORS update time.
Each subsequent ORS update books flights departing in 72 hours in the future between the given ORS update time and next ORS update time.