Revenue Threshold for Business Reversion: Is This Typical?

I’m starting with a new agency, and I’ve come across an interesting commission structure for new business. It specifies a minimum sales threshold of X. For every role closed, the initial X amount is allocated back to the business, and the commission percentage is only applied to the revenue exceeding that threshold.

For example, if the threshold (X) is set at $1K and the total revenue generated is $20K, the commission percentage would only be applied to the remaining $19K.

Is this a common practice in the industry?