mecabq

I still don't really understand the logic. At the St. Regis Singapore, the room hierarchy is as follows:

Executive Deluxe
Grand Deluxe
Lady Astor
St. Regis Suite
Caroline Astor Suite
Manhattan Suite
. . .

I would like a room with two beds; apparently only the Grand Deluxe and Lady Astor have these rooms.

I first booked the Lady Astor Room (with two beds), and it offered me an upgrade to the St. Regis Suite (with one bed). Fine. I then changed the reservation to Grand Deluxe (with two beds), but the only upgrade it offered was to the St. Regis Suite (with one bed) -- skipping a category. Why?

So my two options are to book the Lady Astor Suite with two beds and forget about the upgrade, or to book the Grand Deluxe with two beds and forget about the upgrade.

I realize that I could possibly get a roll-away-bed, and of course I am fine with the strategy of just booking what I want. But this is yet another case, just like every time I have tried, where the Suite Night award is not very useful. Why can't I book the Grand Deluxe room (with two beds) and go for the upgrade to the Lady Astor Room (with two beds), since it's the next category up? That way, I am assured of what I want whether the upgrade clears or not.

Relatedly, it seems like there is no way to tell before committing the reservation what upgrades will be available. Frustrating.