I pull them off at 140-150 internal, then slice and pan them. Pour a little marinade over them, then cover with heavy duty tin foil and put them back in and let the juices tender them up. About and hour and a half later, they are so tender that you don't need a knife.
BTW, I get my tender loins at Sam's by the box load. I cook them for event lunch's. I start them at 6:30 AM and have them on the table at lunchtime. I've done it this way for years and have more than my fairshare of 'attaboys' after they wrap their lips around da meat. I just did 4 this past week for a hundred of my closest friends at a charity golf tournament in Arkansas. I had some custom packed smoked sausage to go along with the loin, beans and tater salad. All I brought home was the pit and the tools.
Well I buy my loins at sams too. I soak them in apple juice no longer than 3 hrs then coat them with yellow mustard then my favorite rub. I pull mine at 150* internal temp wrap up in foil and a towel let set for 1 hr then slice up.