On the case of no more than 3 people having a leve, and at least one of them has double, col M would not be correct.
e.g. 2 2 0 0 0 0 0 0 -> 1.00

Considering only the less informed players would use this sheet, you might also want to categorize the leves by the camps. And add a warning for when the leve is too low ranked for the party even at 5 stars.