Hi folks, thanks for getting in touch. This kind of thing is quite nuanced to balance as we're dealing with a myriad of variables here; Simbrief's data and calculations, our data and calculations; winds in the sim maybe not matching the predicted as closely as expected; cost indexes; procedural approaches adding more burn; the A310's notoriously problematic VNAV (IRL). The data we have provided for the profile is the same as that in our manual, which is what we use for our calculations in the sim. Having just performed a flight, I landed with 800 kg less than planned on Simbrief; however this is including what appeared to be several wind shifts at cruise in the sim, and following the full procedural approach to the ILS, which is not factored into Simbrief's calculations.