BF4 only has scaling for iron sight and 1X scopes, all other scopes have fixed FOV (unless I missed an update?).
BF1 on the other hand scales all scopes.
You are doing it correctly for the scope you have selected, and I would suggest also using the "Config File 2" calculation for PUBG so you get the other value for the config file. This makes the slider in-game correctly represent your sensitivity.
Viewspeed matching sensitivity based on the chord length of the arc of your FOV. To make it simple, it's about the same as Monitor Distance 70%, or about the same as USA 1.25 in Battlefield.
(You had a double post, deleted the other one )