(12b) Gross Vehicle Weight Rating (GVWR). – The value specified by the manufacturer as the maximum loaded weight a vehicle is capable of safely hauling. The GVWR of a combination vehicle is the GVWR of the power unit plus the GVWR of the towed unit or units. When a vehicle is determined by an enforcement officer to be structurally altered in any way from the manufacturer's original design in an attempt to increase the hauling capacity of the vehicle, the GVWR of that vehicle shall be deemed to be the greater of the license weight or the total weight of the vehicle or combination of vehicles for the purpose of enforcing this Chapter. For the purpose of classification of commercial drivers license and skills testing, the manufacturer's GVWR shall be used.