Technically, proper analog component and HDMI should be equals for the scan rate/bandwidth they were designed for.
How a display deals with them is another story and there is no consistent response - it has to be tested. As an ISF calibrator I always have to assume that a different scan rate or input may have a different response until proven otherwise due to experience.
David, that means your test is not conclusive for all users - just for you and even then nobody is sure why. Beyond video setup, it could be your cable box is lacking instead of the display...
Thanks Richard. Unfortunately, there are only three calibrators listed for Michigan. Two of them do not have any tours to Michigan planned which are not already closed. The third's web site is a little low tech and I have to contact them to find out when their tours will be.