I think more and more restaurants are forgoing the extra plate charge when patrons want to split an entree, salad, or other portion of a meal. Given how big some portions are these days, it's not just economical, but sometimes healthier, to split portions. It never hurts to ask.
Lunchtime seems to be the best way to enjoy a more expensive restaurant.
My DH and recently took my mom to Emeril's restaurant at Universal Orlando. My mom and I split a salad and entree at lunchtime with no problem. There was no additional charge, and the waiter was sure to give us extral plates to share the food. We had a wonderful meal, shared food among the three of us, and didn't feel overstuffed at the end of the meal.