Editing Civil 3D Surface using Edit Surface command

[louise.hilton861522]

I am trying to add points into a surface. I have done this before without any problems, but now I am having issues.
When I ID points which makes up the surface it gives me the correct Z level eg. 24.5m, however when I hover over the surface it shows me the surface name and a different z level eg 0.65m. Can anyone explain the reason for this difference in z levels? I think this may be causing the issue I am having when I add new points.
I select the surface and use the 'edit surface comand' in the ribbon, choosing add point.
When I add a point at the level I require(23.89m), it puts it in a lot higher than the surrounding area, so I tried to put the point in to the lower z levels (0.4m) it puts it in a lot lower!
Any help on this matter would be greatly appreciated, as it is now beginning to slow my work progress, as well as driving me to distraction.

[louise.hilton861522]

With the help of other users, I have figured out my issue with this. My drawing is (for some unexplained reason) set to inches instead of metres, which is what was causing my problem