http://iscoresports.com/

It's about a Softball league with a maximunm of 7 innings of play

At the beginning of the season, I've clicked every 4 icones located on le lower right side of the iPad along the frame... curiosity!!
With the last one that looks like a mechanic wheel, we can fix the maximum number of innings of play
I remember having fixed to 9 the number of innings of play BUT we have never played more than 7 innings.

QUESTION :
Would there be any consequences in stats calculation (pitchers...)?

If so, is there a way to correct that?

Setting the max innings controls ERA and the automatic end-of-game after 7. The ERA stat is based on this setting. The ERA9 is the typical 9-inning ERA calculation. You would have to change all of your current games and recalculate the stats if you wanted your ERA stat to be based on a 7-inning game.

OK
when you mention

You would have to change all of your current games and recalculate the stats if you wanted your ERA stat to be based on a 7-inning game

after having reconfigurated all the games at 7 innings of play, does iPad recalculates the stats or will I have to do it game by game?

It should recalculate as you change each game.