I believe this to be good advice based on my experience. If you call outside business hours, you'll get connected to a call center in India where staff appear to be less well-informed. Though to be fair, some domestic staff are also not that well informed on the use of club upgrade certificates, but at least I know that I'll udually get my question resolved if I stay on the line.
That is so true. If only they were as easy to use as FNAs. I recently spent more than three hours on the phone getting a club upgrade certificate applied to a reservation. At first, I was told that there was no club available at the time of booking but was told to contact the hotel directly to ask them if they could open up availability. The hotel said they would open up availability and that I should call the luxury service line to book. I did so but was told by the rep that no availability was showing, so I was again told to contact the hotel. This cycle was repeated four times with four differnt people from the hotel without resolution so finally a Bonvoy Resolution Specialist got involved and the same thing happened again. Finally, it was resolved, but it is such a needlessly complicated, time-consuming, and demoralizing process. Also, I have never received the $100 property credit together when using the club upgrade certificate. I'm not sure why.