More kudos to being publicly involved in the product improvement.
Mike, correct me if I am wrong, but it sounds like your approach here is to create a throttle body bore and blade that closely matches the behavior of the smaller production GM units at low throttle area where the Cd is most critical. I'd say that's a pretty cool way to solve the problem, and it sounds like you've succeeded, based on your internal testing. Could the outlier you found and the throttles that your customers here have worked with be just production variability? If you can take a poor performing throttle back as a return from a customer and send them one in its place without changing the product itself, it isn't the product that has an issue...rather variability in the manufacturing. Food for thought I suppose.