Ray Andraka wrote

The other surprise to me was that they claim multi-weight oil is
bad for corrosion resistance if the airplane is not flown very
frequently (a couple times a week) because it drains off too
quickly. I vaguely recall seeing a similar claim a while back.

Ray, do a search on the Lyc o-320H engine. The "H" engine had a real
bad habit of cam failure until the FAA put out an AD mandating that a
particular additive be used in the oil. This seemed to fix the
problem, I taught in one particular 172N for six years with never a
problem. The additive was so good, that it is now a standard
ingredient of the AeroShell multigrade oil. I see this "snake oil"
being sold over the counter at Sun n Fun, but the name escapes me
right now. I would't switch if I were you.

Bob Moore