Ted, that would generally jibe with my experience. The blatant print flubs predominantly are from the white stock run. I do have (I am looking at it but cannot seem to find a scan of) a gray back Zivic with missing background color, but that is the only missing ink card i can recall in gray, though clearly there is at least one sheet of them that made it out of the factory.
One more idiosyncratic observation: I recall a higher number of ghost prints with gray back cards. I suspect the paper was 'thirstier' than the white stock and more easily fouled.
