Cut roast in half; place in a 5-qt. slow cooker. Sprinkle with seasoned salt and garlic powder. Pour 1/4 cup cola over roast. Cover and cook on low for 4-5 hours or until meat is tender., Remove roast; cool slightly. Shred meat with 2 forks and return to slow cooker. Combine barbecue sauce and remaining cola; pour over meat. Cover and cook on high for 1-2 hours or until sauce is thickened. Serve on buns.