Hi Wayne! Is charge depletion mode for the plug in or is that the system were the HSD cycles the battery on its own? I if it was me I would be using Top Tier fuel in my baby! TOP TIER Gasoline Retailers: USA Canada 76 Stations Chevron Canada Aloha Petroleum Esso Chevron Petro-Canada Conoco Shell Canada CountryMark Entec Stations Exxon Hawaii Fueling Network (HFN) Holiday Stationstores, Inc. Kwik Trip / Kwik Star MFA Oil Co. Mileage Stations Mobil Ohana Fuels Phillips 66 Quik Trip Rebel Oil Road Ranger Severson Oil Shell Texaco Tri-Par Oil Co. U.S. Oil Also I ran oil sample reports on my C back at 1000k and 5000k and 10,000k miles and the original oil held up well so I would leave it in, in case you want to change it early? I have also been told factory oil has break in additives you want to keep. Almost no wear metals and the Toyota 0-20W Synthetic is one of t best oils! Many good reviews on it the bob is the oil guy site!