We had a fairly lengthy discussion about this in a thread earlier this month.
There’s no objective definition of this, but I set the piling on point higher than 6. Even if 4 is the point where the winning percentage gets close to 50%,a few additional runs can significantly increase the winning percentage. They also can provide some cushion that allows the team to avoid using its top line relievers.
But when you get up to 9 or 10 that’s usually more often than needed for a comfortable win and additional runs from there can pad the statistics without helping the win percentage.
By having more games of scoring 5 or 6 runs and fewer of 10 or more and 3 or less, the Brewers have been able to maintain a winning pace while slipping in MLB scoring ranks.