thats an interesting site!
Those detailed data come up for "verified users" only?
Those loading data look quite right.
I havent seen such detailed data in all my pre-WW I catalogs (Roth, DWM, Utendoerffer).
It seems those Czech or Slovak ammo factories continued loading the old BP cartridges after WW I, maybe even after WW II and started to measure decent ballistic data?

what sort of black powder?
Who generated or collected the data?

My approach would be to choose a comparable bullet and not exceed the velocity given for the BP load.

Checking your loads with a chronograph is a must!

VV powder means Vihtavuori?
I have never seen any data published for VV powders as BP substitute.