Ihave the seem problem and i test that is the FSINN, i tried whitout Vatsim and in the FMC the OAT was 0%, then i used Active Sky Evolution (whitout Vatsim) and the OAT was 11% on MMMX airport (the real weather's moment), then i tried whit Vatsim and no ASE in the seem session and the OAT was 25%, my conclusion was that the FSINN don't work's great whit PMDG product's.