Ellipsoid height given points on Globe?

Do the elevation input arguments to ecefOffset.m require height of actual ellipsoid or the height above the ellipsoid? I'd like to compute a spatial gradient, in 3-D for a point 200km below Earth's surface.

I couldn't find a clear example of a function that simply gave the distance between two points in 3-D when the point was near but not on Earth's surface.

I have access to Matlabv 2014a, with the Mapping Toolbox.