Too much haste? Mastery needs <3 too?

Hey guys!

I am currently sitting at 2191 haste rating 78.55%(+17.11%), but my mastery is only at 22%, a rating of 563(3.17%). Since haste is multiplicative, or so I've read, at what point would it be a good idea to slow down on the haste and maybe beef up mastery a bit? Or at this point in time with the level of gear currently out do we not have to worry about it yet and just keep getting as much haste as possible? And btw my spec is 2H Frost. Thanks :D
Pretty sure at this gear level we can't have to much haste. If your gear has haste on it already then reforge the secondary stat to mastery as long as you can stay hit/exp capped but otherwise haste is our best stat. More swings = more procs