I looked into "buying up" for an open jaw ticket into Rome (FCO) and out of Zurich (ZRH) in March. The difference between an advance purchase B ticket (BLXxxx) and an unrestricted B (BUAxxx or B) to qualify for the extra EQM was also about $1200 ... $1100 vs $2215. So it wasn't worth it to me. As a rule, unrestricted B fares do not vary very much. Restricted B fares do! So if you want to use less miles for an upgrade then do shop around! I just returned from DUB via LHR and ORD and paid $1004 for an advance purchase B and used 15,000 miles to upgrade each way into business. An M or H ticket was $864 and a "cheapo" W was $668. So not a huge difference given that it was a weekend trip ... out Thursday night and back yesterday afternoon ... and I got to go biz and relax a little and sleep.