There is nothing wrong, at a non-buffet, non-all you care to eat restaurant with ordering 4 meals, and an extra drink, and sharing it with 5 guests, with only 4 being on the plan. Sharing food is OK
Chefs de France only allowed me to use the DDP to pay for 2 meals, my card said 2A. I asked at the desk at POP and was told you're not allowed to use your meal plan to treat guests not on the plan.
It's certainly possible a server at a particular restaurant may be able to make an exception but I wouldn't plan on being allowed to do that.
DIS doesn't want us debating the use of the plan, some guests were allowed to use credits to treat and some weren't. YMMV.