That is advice from the Brewing Supply store. This is my advice:
Leave your beer in the Primary for 3 weeks. It won't hurt the beer, but I think it will not only help clear it up, but also make it taste better. That is my standard primary time, which is sometimes extended for stronger beers.
Also, if you want clearer beer, try not to move the beer at all until you transfer into the bottling bucket. It doesn't usually take much agitation to stir up the stuff on the bottom. I usually just try to be very careful when carrying my fermenter into the kitchen on bottling day, but a better idea would be to place the fermenter in a location that would allow you to siphon without moving (countertop, table, shelf).
You could rack to a secondary after a week, if you like, but I find that a usually unnecessary step in the brewing process. I think it's been shown that a few weeks on the yeast does no noticeable damage to the flavor of beer, and may actually speed the conditioning.