I guess AA's policy is to reissue for any and all changes - I was surprised with this since my previous xONEx experiences were with CX and QF where basic date/time changes were revalidations.
My first xONEx was actually with CX ex CMB and the 'ticket' was 5 books of 4 coupons (oh those were the days
). A schedule change mid travel* required a re-route half way through and they send me a new set of coupons (only those flights remaining). Other than that, all changes simply showed up online.
* Travel was taken over 12 months with lengthy mid point breaks.