I've found that sometimes, you need to check both the main website and the IHG app to see all of the rates. I frequently stay at an HIX with a 5K bonus rate (as well as 1K, 2K, and 4K rates--strangely, the 4K rate is more expensive than the 5K rate). I can usually find this rate on my computer, but every so often, it isn't a listed option. I've always found it when I go to the app although there are some other rates that I don't see in the app that I can see on the website.
I once booked a 20K bonus rate at the Indigo in Brooklyn. I had to contact IHG when the points were delayed posting, but once they posted, they all counted for Spire status.