Inventory can change at any time, so keep trying your corporate rate as you get closer to your desired date. I make a habit of this even with a confirmed room! Sometimes there are specials that can beat what was available earlier. Just remember to check your cancellation date and don't cancel until the new rate is booked!

Discussing corporate rate processes is fine, disclosing the actual rate codes is frowned upon (even though many are public). When looking for the best rates, I check property specials, corporate, AAA, and selected rate codes. Even for national rates like AAA there can be a significant difference in neighboring properties. It is up to each property to load the rates they are willing to accept.