Most of us would recognise VS - vertical speed, or ROD - rate of descent , but you are the first one I have heard using Vz in 32 years in the industry.
So, bullsh1t it may not be, but you are trying to invent (or at least introduce) a new acronym that it seems we are all unfamiliar with, why ?
Again , it all smacks a little of "the new kid in town" trying just that little TOO hard to impress.
Anyone can sit and digest reports and pontificate about this that & the other, but really, what REAL experience do you have ?
You said in an earlier post that you had suffered an emergency in which you were greatly helped by intervention from the ground.
With the greatest of respect unless you are a poor little PPL student lost in IMC and sheperded home by ATC , I doubt, if the situation could be influenced from the ground, that it could be categorised as an "emergency".
Losing both engines on short final in a twin engine wide bodied transport category jet aircraft. This you know off pat, EXACTLY what to do Eh ?
I am sorry guy, but you truly come across as a smart-ass armchair pilot, you can analyse everything, but did you actually, in your aviation career, do jacksh1t ? somehow I doubt it.