HOW MANY STALLS OF HORSES DID SOLOMON HAVE?

I Kings 4:26 And Solomon had forty thousand stalls of horses for his chariots, and twelve thousand horsemen. (KJV) II Chronicles 9:25 And Solomon had four thousand stalls for horses and chariots, and twelve thousand horsemen; whom he bestowed in the chariot cities, and with the king at Jerusalem. (KJV)

There are two possible explanations for this.  One is that there were four thousand stall buildings, each of which had ten separate stalls inside.  This would mean that four thousand stalls, and forty thousand stalls, are both true, just counted differently.  Another is that the authors of 1 Kings and 2 Chronicles were counting at different times in Solomon's 40-year reign (though I find this one questionable, since I doubt he would have seriously increased or decreased the number of stalls, while keeping the number of horsemen the same).  And since it's off by a factor of exactly ten, this could also be a copyist error, not reflecting on the original texts.  There are enough possible explanations that we can say this is not a contradiction.