So let me get this straight --
If you are Platinum and fly 4 H/S/Js you will be Chairman for 19 months.
If you are Chairman the is nothing you can do to extend your status that long other than fly the regular 120 segments / 100k miles
I find it very hard to believe that everyone but Chairman's members can take advantage of this promotion. Though maybe I shouldn't. I put an e-mail into the CP desk we'll see what they say.