Heat oven to 450°F. In small bowl, mix together chili powder, Adobo, cumin, dark brown sugar and cinnamon until well combined. Stir olive oil into Adobo mixture until completely saturated.
Using paper towels, pat pork loin dry. Rub pork all over with Adobo mixture. Transfer pork to foil-lined roasting pan. Cook until pork is dark golden brown and instant-read thermometer registers 145°F when inserted into center of loin, about 35 minutes.
Transfer pork to platter; tent with foil to keep warm. Let rest 10-15 minutes before slicing. Serve with accumulated juices.