That is presuming Carson had that many votes to begin with which would be way higher than his polling average.
Of course.
At any rate, it’s a big assumption to say 4 Carson voters in every precinct switched their votes in the first place.
Maybe it was 1 out of every 5 precincts who switched their votes to Cruz, maybe none at all. Maybe some switched to Huckabee or Santorum or Rubio.
There are any number of pretend scenarios that would change the math Rove was so giddy about.