Two Types of Weeding give different results

Been playing around with weeding polyline contours to get my drawing file size down and have found that the mapclean –> weeding command gives different results to the featureline weeding command, not sure why at this stage but with the same settings the map weeding only removes about one third of the vertices that the featureline weed does. But the featureline weeding is very slow in processing a large number of polylines in one hit where as map is a lot quicker.