Our first 2 trips we provisioned with the moorings provisioning options. It worked out well both times, but we did have food left over. A lot less the second trip. 3rd trip we used Sunsail provisioning which allowed us to choose from a list of items, rather then picking specific meals - more like shopping at a market. Last trip we used Bobby's and will probably use them moving forward. It's a spreadsheet and you just pick the items you want and they deliver it.
What we've learned after our 4 trips now is that eating out adds up very quickly. I don't think we've ever spent less than $100 between my wife and I for any dinner. So the $200 per person we roughly figure for food really doesn't seem so unreasonable. That still leaves us with a few meals ashore, such as a couple of dinners, maybe a lunch and/or breakfast.
We also don't get everything right at the start. We've stocked up at Soper's hole, VGYH, Leverick Bay and Scrub Island. It doesn't take long and they have most things you need.
The biggest thing to think about is how much will you want to eat ashore vs on the boat? That's really the biggest factor in how much you should order. For the first trip, its really hard to know, so you could always provision less to start.