Bleh. EMECO came back and said this itin was 35900 miles, but on GC it's only showing 33900! What distance calc are they using?

Also had a similar issue with AA oneworld award calc recently, the mileage came out several thousand higher than the great circle routing..
CAI-LHR-LAX-SYD-POM-SYD-HKG-NRT-HKG-BAH-AMM-BAH-CAI