The chart you linked to uses a combination of both hard and soft filtration (magenta and yellow) for each grade. This method is designed to keep exposure times about the same for each grade. However, in doing so, it uses a lot more filtration that just using either magenta or yellow, and causes longer exposure times. By "multigrade" paper, if you mean Ilford's Multigrade, there are filtration charts included with each pack or box of paper that gives individual values for yellow or magenta as well ans the "balanced" method. It's also on their website (see below)

Adding any filters will increase exposure times compared to white, unfiltered light. There are no "normal" printing times, as there are too many variables: paper, enlargement size, light source, density of negative, etc. So, you have to meter and/or make test exposures for each negative and print size anyway. To me, this negates the advantage of balanced filtration and the longer exposure times. I would recommend using the single filters.

See: http://www.ilfordphoto.com/Webfiles/...8932591755.pdf

The Ilford literature uses "single colour" and "dual colour" to refer to the yellow or magenta (single) or both (dual or balanced).

Good luck.