The more you generate, the more you get. I.E., Company A gives 10% commission on all sales. Performance Incentive means that for total sales above $5,000 for the month, they will increase your commission 50%, to 15%. Some companies also give set bonuses as P.I. Company B may give a $150 bonus each month for sales totaling more than $5,000.
If you generate alot of sales, usually on the end of moth got bonus incentive. So Performance Incentive is how much money you can get only from bonus.