I'm aware of the winds aloft issue. The 767 version 1.2 seems to have far less range than the 1.1 or the 1.0 versions. When I put in a flight from Frankfurt to Los Angeles with 1.2,the FMC calculated insufficiant fuel well before reaching LA. This is a 5476 nmi flight with no passengers or cargo. When I reinstalled 1.1,the same flight was calculated to have fuel to spare. A 5476 nmi flight that is listed on Boeings website as a typical city pair,isn't possible with version 1.2. At least that's what the FMC is indicating. Have you tried any long flights in the 5000 nmi range or greater? If I swap out the FMC gauge from the 1.1 or the 1.0 into the 1.2,I get better fuel calculations but I lose the weather radar which seems to be coded into the 1.2 FMC gauge.