Not Bad, Gives a good approx Time with some reserve allowance.
I guess its Hard to really make something for all situations as Lipos
Have so much variance with Total Actual Capacity, C Rating, Actual Condition of Lipo as Well could affect Times.
Always Remembering that this is Full Throttle Discharge which not many do.
Great Guide Though for ones unsure of how long to stay up in Flight as on average you should well go past the full throttle time frame.
Maybe you could incorporate a average throttle position in the equation.
Eg Stryker with 2250 40c Rhino lipo
Full Throttle 70 amps at start then its about 60 afterwards battery gets down in voltage.
average throttle postion when flying amps is about 15-25 amps
so i normally get 8 minutes + flying done to 3.7v