Yes, as an IB/Affiliate you also earn IB/Affiliate lot commissions from your sub-affiliates and their client networks.
From your direct sub-affiliates (their clients), you earn $2 per lot.
From the clients of your sub-affiliates’ clients (one level further down), you earn $1 per lot.
This allows you to earn not only from your own referred clients, but also from the trading activity generated by your extended sub-affiliate structure.