explanation of sheet of a conical of a helical scale

[Ilario]

therefore the "performas" of the idw do not exist.. . .

 

[ForFlight]

therefore the "performas" of the idw do not exist.. . .

I don't want to be polemical, but why does the inventor's manual talk about more performance for the idw? the manual says: dwg for those who want more interchangeability (what obvious), idw for those who want more performance!