Not to be rude or disagreable about production runs; as a person who has spent years studying printing from the ancient times to the modern times; the printing presses that Pro Set used printed roughly 5.25 two-hundred card sheets a SECOND and so for their to only be 15 of any particular card is hard to believe EXCEPT for the fact that when they found an error, they threw a batch a way. A double print sheet would only happen by the wrong pile being fed into the obverse print machine. They would catch this as soon as they started printing. It takes about 8 seconds to hit the ALL STOP button. That would mean at least 44 sheets came out like this...
Most of the card sheets misprinted were disposed of. Lud Denny was known to come by and grab a print sheet off the test pile. In 1990, the test sheets for color and alignment were Jerry Rice and those are some of the rarest individual sheets but even those were thrown away.