While I don't have the specific answer to your question I'll share what I do know.

When we provisioned for a few years with Bobby's there was no additional fee to anything for dockside delivery. While that was convenient we have learned we wasted a lot.

We now go to a store when we arrive and self provision for 3-4 days by buying what looks good when we are in the store. There are plenty of places around to grab a bit more bread (avoid rapid spoilage by keeping it in the fridge) beer, rum, other food and fresh pastries.

The first two charters we spent $600 (4 people) and $800 (6 people) on food. We just returned from a trip and spent about $300 (4 people) with very little waste. We traditionally will have dinner on shore.