You're already 564 as a group and it WILL go up substantially before you reach the last bosses considering you raid 6 hours a week. Can guarantee you'll be 570+ when you hit siegecrafter, probably 575 when you kill Garrosh.
And if you don't want a blanket nerf affecting you then you'd better get in there quick, if you wait 3 months or more theres a good chance one will be in.