Preheat oven to 350°. Bake tea biscuits according to package directions. Cool on a wire rack 20 minutes.
Preheat grill to 350° to 400° (medium-high) heat. Remove silver skin from each tenderloin. Sprinkle salt and pepper over pork; rub with olive oil. Grill pork, covered with grill lid, 10 to 12 minutes on each side or until a meat thermometer inserted into thickest portion registers 145°. Remove from grill; cover with foil, and let stand 15 minutes.
Meanwhile, cut biscuits in half, and brush cut sides with melted butter. Arrange, cut sides up, on a baking sheet. Bake at 350° for 8 to 10 minutes or until edges are golden.
Cut pork into 1/4-inch-thick slices (about 24 slices each). Place pork on biscuits; top with desired amount of Cranberry-Pepper Jelly and watercress sprigs. Serve immediately.