How strict is the 10 day rule?
Can you ticket with an original itinerary of more than 10 days and then make a regular reservation and show up with your paper ticket for a different day on the same last flight (winthin 10 days for your return/last leg) flight and be OK.
Or, can you continue with a non-important last segment leg as an unused last leg, such as:
Day 1: BOS-PEK
Day 5: PEK-HKG
Day 7: HKG-JFK
Day 11: JFK-BOS
Then buy a oneway seperate JFK-BOS segment on Day 8 outside of the itinerary?