Many business owners understand that paying salespeople (straight) commission is a great way to motivate and reward them equitably for their performance. You chose a commission rate that is acceptable and put it in place.
But when a salesperson begins making more than you, your inner dummy can come out. “I’ve got to stop them from making so much!” May as well say goodbye to the winners.
Them making more than you means they are doing their job well – and you aren’t doing yours well!
Keep your winners and straighten out the guy who’s messing up instead.