Fuel Economy on 6.2L EcoTec3 V8 with the 8 speed Tranny

Our former k2500 Suburban with the 8.1L and 3 speed towing 7500-8000lbs was 6-8 depending on the hills and 11 around town. Our 2015 F250 6.2L 6 speed 3.73 rear. Around town its in the 14's. Towing 12.5. Very impressed. I was concerned with getting a gasser and wanted a diesel, but Im very happy with the gasser as we only tow 20 days or so, and I didnt want to pay the diesel price penalty