Any idea if when upgrading from Gold to Platinum (organically through the number of nights), you get a new set of 20% coupons and the old ones become invalid?

I have 48 nights so far and have an upcoming stay of 21 days, so I am thinking to split in 3 bookings (2 +8+11 nights), so that I can use the platinum benefits such as the lounge after the 2 nights post a week later.

On a separate note, while 2000 points give quiet a good value discount, anything above is poor use of them.