i had to lower a surface recently and i did it globally with the move command, granted it crashed on me several times no doubt. i picked only few features at a time, changed the color to something unique until all of it was lowered.
if you use the raise/lower edit command from the surface menu, how do you get it to tie out. none of the feature lines move, just the contours.
after i lower my surface using the slow method, my fg surface in profile view moved. i would have been made had that not been the case.