I charge about the same as the above. I have an abundance of serveware including stands. Because I have the items for a future retail store, I charge a rental fee for the pieces in a quote. But if the client will consider a mini buffet, I will provide the serveware for free with a deposit equal to full retail value. This one issue has made all of my weddings and events a multiple item mini buffet or full buffet. And I already owned the items anyway.
Another revenue builder... I don't charge a deposit if we have a paid attendant at the event. We now have every wedding and event with a paid attendant. They set up, serve, clean up and pack up. If someone is going to break something, it will be us. Once the client sees it on paper, it makes the event so much easier when those details are eliminated from the client's responsibilities.
For my best customers, all rentals are free and they can have as much as they want.
It is so easy to build an order far beyond the cake and a stand. People want something special. You just have to make it easy for them.