Hi - recently had my heat pump serviced. Just chatting with the technician I mentioned that my house is always warm in the summer (we keep it at 78 and the master on the first level gets up to about 82-83) and cool in the winter. This unit is servicing approx 4500 sq ft (ranch style with finished walk out) - he stated that on some older Lennox models the calculations were off by Lennox. Is this a correct statement? He got back with me and the ARI ratings show this unit to be 3.17 ton with my coil (C26-41) and not 3.5 ton.