I was unable to use the "multi-quote" feature but svo242 is quite right sadly. This property used to do a pretty decent job with things like upgrades, extra free breakfasts etc. My last stay there (January of this year) was a completely different story. Despite having a number of suites available, they refused to upgrade us. I had a nice chat with a then front-desk-manager who explained that their revenue department actually forbids them from upgrading beyond a "grand-luxe" room (St. Regis speak for 'identical to a deluxe room but slightly closer to the ocean'). While I did not need a late checkout, I have little difficulty imagining them declining. In fairness they are a resort (I believe) and therefore are not obligated to. Very good hard product but nothing like the near perfect service experience we enjoyed in February, 2020 and earlier.

Our experience at the Ritz Carlton Bal Harbour was almost the complete opposite. In fact, we moved from the Ritz to the St. Regis on Jan 1. The Ritz had no problem with granting our late checkout request (although they too are not obligated to as a resort). If the pricing is comparable, I would totally switch to the Ritz. You might want to call and speak with a front desk manager (before cancelling the St. Regis) and asking about this. If you have >= platinum status, they may even agree to free breakfasts if you are paying cash (as a Ritz, they do not have to).

Both great hotels...