i was trying to do a multi segment from pit to san through iad then back to pit then to san then back to pit again. for upgrade purposes, i set the itin to pit-iad-san which cost $550. then the second itin was san-iad-pit-iad-san-iad-pit (with a stop in lax automatically generated between one of the san-iad) and that itin was only like $630. granted these prices were only like a week in advance so i ended up purchasing both itins for like $440 total for a month later (which i am about to fly).