Help with the definition of 'first play'

In a HS game there are Runners on 1st and 2nd who are off with the pitch. Batter hits a groundball to the Third baseman who knocks it down and than begins to run to 3rd base for the force. He than realizes that it is too late and throws late to first base and the ball goes out of play. The umpire first rules runners on 2nd and 3rd, one run in but than changes the call to runner on 3rd 2 runs in stating that the throw was the second play. Was the act of taking a couple of steps towards 3rd base correctly called 'the first play'