I get a 'Significant Organization Savings' rate. It will always show that rate on the first page, but then when I go to book will show that rate as sold out. Turns out that if the rate is shown on the first page, it is available. I have found 2 solutions that gets the booking page to show the rate. Sometimes, refreshing the booking page several times will get the rate to show, but often I must log out and then log back in in order to get the rate to show as bookable.