I received the following from the hotel after I asked what the Ambassador upgrade would be for:
INTERCONTINENTAL HARBOUR VIEW ROOM
INTERCONTINENTAL DELUXE HARBOUR VIEW RM
SUPERIOR JUNIOR SUITE POOL VIEW
Maybe my reading comprehension is not good but I thought this was a very confusing answer...
Looks like previous status-quo is being maintained. For ICHK room upgrade path the previously non-bookable Superior JS is ignored (unless you have booked it)
As an Ambassador a 1-Cat upgrade is applied on paid nights.
Deluxe -> Harbour View
Harbour View -> Deluxe Harbour View
Deluxe HV -> Deluxe JS (note 1)
Superior JS -> Deluxe JS
Deluxe JS -> Exec Suite
Exec Suite -> Deluxe Suite
Deluxe Suite -> No upgrade Given
(note 1) For an Ambassador although intent is Dlx HV -> Dlx JS upgrade, if not enough Dlx JS rooms available then Ambassador may instead receive Dlx HV -> Sup JS