Why didn't you just use the RC/Grand award level for your stay? That's what I would have done. Yes, it's 3k more points a night .. but if that's what you want, then it should be worth it. As a platinum member, there's no guarantee you'll get an upgrade or get offered RC access, or get coupons in lieu of access. It only takes 5 stays to make plat. The one decent benefit is the "extras" coupons at that level.

At that property, heck, you probably could have had them upgrade your award to the RC level award if you were willing to use the points.

GP award chart

-David