TCI6630K2L: K2L Power Spreadsheet Lower Clock Rates

Part Number:TCI6630K2L

Hi All,

I am investigating the use of  a Keystone II processor for a device that will operate in different modes/configurations.   One of those modes will be power constrained, and or this mode I won't need the full CPU throughput of the device.   I'd like to clock it back to a few hundred Mhz to save power,  but the Power Consumption Model (66AK2L06_Power_Consumption_Modelr1p0p5)  has a minimum CPU rate of 800 Mhz.

So...  2 questions

1)  Is there a reason that I can't clock the device lower than 800 Mhz ?    I don't see anything in the Datasheet on cursory inspection.  Is this just a limitation of the spreadsheet. 

2)  If I can clock at say 400Mhz, Can I extrapolate the data below 800Mhz ?   Or is there a reason that this value is clamped to 800  in the spreadsheet. 

Thanks, 
Jim