I too add the recommended amount during the last 10 minutes of my boil. I do rehydrate the wyeast blend, only cause they say to... not sure why it's needed but hey... i guess they have a reason. I also add a pinch to my yeast starters. I boil my starter wort for 10 minutes so I toss it in when it reaches boiling.
I've done two methods. Adding 10-15 min in the boil, or boiling it with the rehydrating water to sterilize it, let it cool, then adding the yeast to rehydrate. I've done the latter because I've read that certain minerals can fall out of suspension when you chill the wort. This way they are added post chill.