LCr4500 at 180Hz 7-bit grayscale

I am attempting to use the LCr4500 to interpret each color plane of the RGB24@60Hz HDMI input as a separate grayscale image to create a 180Hz grayscale output.  I understand that full 8-bit resolution per plane isn't available, but assume from table 4.1 in the LCr4500 User Guide that I should be able to use the HDMI input at 7bpp per plane.

I've tried numerous configurations within the GUI without success.  The settings which would seem most likely are

But this always gives a Sequence abort error. 

Is this mode of operation supported by the Lcr4500?  Is it supported by the GUI?