2. Our logic is different because our understanding of the performance requirements of FMVSS is different. These are the minimum requirements for each of the fluids - fluids defined by industry standards (SAE) - and not design guidelines or advice for use in a system.
3. Additionally the weight we each place on manufacturer recomendations differ. I do not dismiss them as simply legal stratagem. For a change to be acceptible to an automobile manufacturer the component would have to pass both design and production validation testing. Those tests usual involve both component and full system testing, in typical and extreme environments, and in sufficient quantity to pass those tests 100% of the time statistically at 6 sigma (or more!).