I just made my first oil change from Mineral oil to Aero 100 after 28 hours on my A65. I noticed that the oil pressure comes up to 40psi when I start it and maintains 40 psi for the hour that I flew but, the pressure dropped off into the yellow when I brought back the power for landing then back up as I taxied in. I had not noticed that occurring with the mineral oil. I'm thinking that this pressure drop off would be normal with idle RPM.