TAS minus GS gives you momentary wind component which is needed for computation of the corrected Vapp (and in this respect, I was plain wrong about measured speeds in my post).
But your equation? Not so, imagine
Vias = 133
Vtas = 130
GS = 120
HW[a/c] = 10
HW[twr] = 10
----------------
GS mini - according to your equation - is 0. That's not how it works.
A32S.FCOM_3.bulletins.820-1A.pdf
Yes, the Vapp increment due to observing GS mini IS 0, but not GS mini itself.
Sorry for being pedantic, but later on you will too realize that proper terminology is essential to understand what are the manuals trying to say. They are complex and easily confusing without us making a mess of it.
Not just academically, but real lifer too. Such as "recycle gear lever" and "recycle gear".
https://aviation-safety.net/database...?id=20130608-0