I don't think anyone is disagreeing here. As I've said, split filtering and single filtering at an intermediate grade, are equivalent as long as there are no differences in local exposure control (ie different burning and dodging actions) during each of the split exposures. If different grades of contrast are required for different areas of the print, then obviously split filtering is different than using a single filter.

Pfiltz - I strongly suggest starting with the Ilford link I posted earlier.