Originally Posted by
stevenshev
There are specific Centurion FHR rates for each property. They give the upgrade, and the free night. Only these rates (and the corresponding room types) are eligible for the free upgrade. You can usually get yourself into suites, but not into any special/unique suites.
A bit late but this is the exact opposite of my experience. When booking a room I was only ever upgraded to a higher room, never a suite. When booking a suite I was always upgraded to a higher category suite.