Well....... if like hundreds of airlines you are using the FCOM advisory information for performance inflight, you must agree the 'recommended brake cooling schedule' is a complex checklist to get acurate result. I give you an example: LW 58000 tones, OAT 33š, KIAS 135, Pressure altitude 1200 FT........ with this values first you interpolate between the value of 60 tones and 50 tones, then the temperature betwwen 30š and 40š, same for speed between 120 and 140 KIAS, then pressure altitude between 0 and 5000 FT........So what happens in real life is that we are busy enough preparing the approach, dealing with ATC and so on that you are not going to start using you calculator for 10 minutes to get exact values......so we round it up to the safe side and thatīs it. Thatīs why I think this app is nice once you have round it up with you operator checklist to be 100% you are on the safe side, to actually see the amount of difference with the actual we are going to have. Happy landings!