not sure if you are running the traverse adjustment or the network adjust. i don t know the background computations that tbc does, and also do not use the traverse adjust. but if you run the network adjust then i do know there is a setting in the setting cog that asks: “perform vertical adjustment”. if you unclick this then vertical is left alone. not sure if you can manipulate the observations how you want afterwards.
if you make all your control points “control” quality then you can also assign different amounts of movement to them in the network adjust. maybe there is a way here to trick tbc into holding the vertical of certain points if you know the vertical is good on them. or letting them move less.
hope this helps.