Can mirror mode work when vertex coordinates are typed in?

I put my project in mirror X mode and then edited a vertex by typing in a new Z value into the vertex coordinate text box. The selected vertex moved. But the corresponding vertex on the other side of the X plane did not move. Is there a way to make mirror mode work for typed-in vertex movements?

Come again and put some images Bro.

No. Use W -> snap to symmetry afterwards or mirror modifier.

Oh cool. Thanks for the help!