I booked 2 nights at the St. Regis Macau for 1 King room and applied 2 NUAs for the Metrpolitan Suite option only.
At 2:37 pm Hotel time T-3, I received an email that my upgrade request had cleared. The local promotion was fantastic, too, with a very (comparatively ) inexpensive rate.
I have only been unsuccessful on two occassion applying SNAs/NUAs in over a decade. Once was at the same St. Regis in Macau, but still upgraded to a St. Regis siute. The second was the JW Marriott Parq in Vancouver that I booked on points 11 months prior for summer 2025 during Vancouver 's largest ever convention. The property sold out 10 months prior. I was still upgraded to a Junior Suite for a 3-night stay.
I have had great success in using all my upgrades each year. I usually only apply them to 2-night or longer stays and have been successful on a couple of Stay 5, Pay 4 redemptions.
James