Well clearly we do as you are confusing the exact point that myperks answered. There are standard Platinum benefits and some properties choose to go above and beyond that. You could change the hotel brand from St Regis to Westin or Sheraton and have exactly the same situation as you are referring to now, just with different additional benefits at different properties.

Just because the St Regis in Singapore referenced the benefits as St Regis benefits, does not mean they are referring to the chain as a whole. I have stayed at the same property and they weren't explained to me in that language, but in the language of the benefits applying to that property.

There is nothing confusing about it at all. The standard benefits are what you should expect and anything above and beyond that are nice to have bonuses. And just for further clarity, I have also stayed at multiple St Regis properties and had exactly the same experiences of the Platinum benefits as you have - it is what it is.