Haven't figured out how QF gets around printing the 20+ line items needed to print a OW RTW ticket. I do know that AA in BKK couldn't do it and handwrote the ticket rewrite (note not reissue). Kudos to the AA general sales agent and staff in an case. I won't even mention the fiasco almost created by adding two VIPs to the LONE4......
back on topic.
I suspect that the AA computer ticket processing is limited to 16 line items and when you change airports you end up with a (allowed) surface segment but handling that on the ticket forces you into an additional line item in the ticket. or 4 of the old style four-coupon tickets.
I suspect I didn't explain that too well and the only confirmation of that would have to be from someone behind the IT wall at AA.
Happy wandering
Fred