Booked mini RTW before I was SE100k, Canada to HND, BKK, SIN, PER, IST, AMS, Canada, all in J for 2 of us -- TPac and TAtl on AC metal. Surcharges were over $1600. Months later when I reached SE100k, I called to change the one domestic flight on the return (SE100k opens seats that weren't previously available so we wouldn't have to have a 6 hour layover in YYZ). That changed caused a reissue of ticket and since I was now SE100K, there were no longer surcharges. Paid $150 for the change, got $1676 refund on SQ.