Are their scales calibrated at the same temperature, or more likely, the refractometer is temperature compensating and the hydrometer is calibrated at 60F Are you measure the gravity at the hydrometers' temp?
Draft 1: Irish Red
Draft 2: Citra Hopped Wit IPA
Draft 3: Honey Brown
Primary 1: Imperial Stout
On Deck: Saison, Berry Wheat, Wit,