A LISN (Line Impedance Stabilization Network) and 1uF capacitor was added to the Generalized Test Protocol for Calculating the Energy Efficiency of Internal AC-DC and DC-DC Power Supplies (Version 6.7.2). The addition of the 50µH LISN provides a known and stable input impedance when measuring the input power factor of very lightly loaded power supplies (below 20% loading) while the 1uF capacitor is used as a low pass filter. Testing at several labs, including OEM labs, showed that the power factor readings were much more repeatable when using the LISN and 1uF capacitor.