OK, I was able to get the rate by going from Le Meridian website homepage rather than Le Parker Meridian page. From the homepage it showed me a list of hotels with the Parker on top, with the $79 rate in the corner. Selecting that gave me 20 prices, with the $79 rate last. No SET was needed. I got one for the 16th. The 26th was also available for $79.
I think accessing the Parker Meridian site directly was limiting me to 12 prices, and so I could never get the low price. I don't really know why.