Autocad lisp allows the user to write level from down stream on the plan this useful for checking and review the level specially if you have many services on the drawings.
Follow instruction below:-
1-Upload lisp (see how to upload the lisp in cad file) .
2-Type in command line level & enter.
3-write actual slope & enter.
4- write text height & enter.
5-write downstream level & enter.
6-Select first point from downstream.