I'm doing exactly what @
rdh0924 is doing in November. I recommend booking it through a portal, which helps shave off a bit of the cost. I inquired about booking the Premium Pool Villa and confirming an upgrade and they said the following: "Unfortunately, our Pool overwater villas, Pool Premium overwater villas and Brando Suites are excluded from the InterContinental® Ambassador program as per terms & conditions. The maximum Ambassador upgrade possible is to one of our Diamond Otemanu overwater villa.". You could roll the dice and then basically pay a fee to upgrade upon arrival to the Brando Suite from the Premium Pool Villa, but unfortunately, in that scenario, you would be paying the upgrade fee for both nights, (which that likely eats into whatever savings you would get) and you would be rolling the dice about availability upon arrival. You also wouldn't get the portal savings on the upgrade price. Overall, I'm in your boat in thinking that this is worth the splurge, but it definitely hurts!