I agree with the other guys that you should slow things down a bit and work the lower notes, growls and murmurs, a bit more. The COD takes very, very little air and breaks over without having to be as aggressively as you are running it, all your calls seem to end on the same note. If you like a call with a lot of "crack" you might want to pick up a reed that isn't shaved and use it in the broken in tone board. If you call the Zink shop they will walk you through the process, someone there is always ready to help.
work on the low end stuff i think you will find the COD has some some of the nastiest, dirtiest sounds out there.
All that being said you will still kill geese with your calling.