I have a terrible upgrade percentage at the SGS. It went from zero % in my first 8 stays, to 100% on my last 2. That's still only 20%, but now I may be on the 'list'.

Whereas I'm getting about 90%(+) suite upgrades, consistetently, with the Plaza Athenee, Le Meridien, and Royal Orchid. The caveat here is that I must book my room at least 4 days ahead, short notice bookings have much lower suite percentages in BKK.

I've said before, the rooms and upgrades are this hotel's weak point, mostly because of the popularity to Plats. No matter, they do many other things well.