Combine marinade mix and orange juice in a large nonreactive bowl, glass 13-x 9-inch casserole or large resealable plastic bag. Add pork chops and scallions; cover and marinate in the refrigerator for 2 to 4 hours, turning occasionally.
Remove chops and scallions from marinade; discard marinade. Brush lightly all over with oil. Set aside on a clean platter or tray.
Grill chops in the center of the cooking grate over direct medium heat to get a good sear. Grill for 2 to 3 minutes before turning.
Turn and switch to indirect heat. Let cook about 15 to 20 minutes or until done. Remember, the thicker the chop, the longer it will take to cook. The outside should be well seared, and the inside juicy and just a little pink.
Remove from the grill and let rest for 5 to 7 minutes.
While the pork chops are resting, put scallions and orange halves on the cooking grate cut side down over direct medium-high heat (increase the heat if need be) for 5 minutes or until flesh is marked and oranges are warmed through.
Remove oranges and scallions from grill and squeeze the juice from half of an orange over each chop.
For a more dramatic presentation, serve a chop, a tangle of scallions and an orange half together, and let everyone squeeze their own orange juice over their meat.