To the paper, yellow and magenta filtration together produce neutral density. However, since the filter is not equal yellow and magenta is going to be confusing to use it as a ND filter because it will alter the contrast a little, in addition to cutting back the light intensity.
Some interesting possibilities:
1) Put an ILFORD #5 in its place if you feel the maximum magenta is not as good as the ILFORD #5. Then swing that into place (instead of the MAGENTA filter) when you need maximum contrast.
2) A fellow on the LF forum with an 8x10 Durst put a YELLOW filter in its place. Now he can split grade print without twisting dials. He has MAGENTA set on MAXIMUM. The "WHITE LIGHT" is now the MAGENTA ON/OFF lever and takes the MAGENTA away quickly. The "SUPLEMENTAL FILTER" lever swings the YELLOW in and out quickly.
3) Or just ignore it if you print only B&W.