Why was this exemption even required? If an LA based pilot (UTC-7/8) operated to AMS (GMT+1/2) then he would still be within 12 hrs. Infact he could continue to DXB (GMT+4) and still stay within 12 hrs. Now as I read the exemtion it is specifically for the sector ORD-AMS, so doesn't allow CX to operate the crewmember on the DXB-HKG or indeed back over the pacific. So why was this required??