You may need to change the floor level in the stories settings so you are not working relative to 0.00 all the time
I think this could be a good alternative, you do mean changing the
Elevation
of the ground floor to be my number? (87.4m)
if I understand it correctly this physically moves my entire model vertically 87.4 m up. (so it's the same as if I had chosen everything in my 3d window and elevated everything 87.4m)
the only trick I found is that I have to change the
Height to Next
number first to a large number so that it could allow me to change my ground floor
Elevation
to (87.4m) then I change the
Height to Next
to my proper number (ie 3.00 m)