What is the difference between "advance" and "advance payment"?

in this context, one answer is that an "advance" means money given against forthcoming money for goods and/or services rendered and that an "advance payment" is money given against goods and/or services to be rendered. 

I've done work for you that you're scheduled to pay me for next week, but I need money now so you give me an advance.

You hire me to do work for you later on and to secure the deal, you give me an advance payment