Originally Posted by
jongesander
I asked because they do not have to upgrade above Club Duplex. The Idul Fitri peak starts indeed from the 21st.
My guess is that they'll be running quite a full house due to the timing of your stay so they may want to see what sells before doing any upgrades.
Especially the Duplex suites (usual AMB upgrade) are often booked by Indonesian families as parents on top and downstairs the day bed can sleep two kids and maid if needed

.
Worst case (hope not for you) they can give 10k IHG points and skip the upgrade.