As I recall from what BAGiant has said in the past, the reset point after the royal is hit is flexible. Where most go back to 4000, it can be 1000 coins higher or more. I'd suspect that any amounts over $10,000 were put into that portion of the pot. So if it was a really, really long time between hits, it might be possible for a $10,000 jackpot being immediately followed by another of the same amount.