First-line sales managers: pay on the team roll-up alone or add their own measures?

Business services company in Paris, 16 first-line sales managers each leading six to nine sellers. Managers are on 65/35 and their variable pays entirely on the team's total against the sum of the team's quotas.

Two things bother me. A manager with one outstanding seller can hit the number while the rest of the team struggles. And some managers are closing deals themselves to make the roll-up, which is not what we want them doing.

Is anyone using a measure such as the share of the team reaching quota, alongside the roll-up? I would like to know what weighting you gave it and whether it changed how managers spent their time.