thanks for your prompt reply. I'm not sure if I get the point. when I provide the service to the client, I invoice him. First, In the Product/Service field, select the services or goods you provided and enter the (100) amount, then I add a new line below, choose the retainer item I set up in the "Product and services", and then enter the -100 amount into the "amount". Now the balance below is 0, which means the client does not need to pay extra money. And my other current liability will decrease by 100? am I right?