It seems like alot of oil companies change their formulas frequently or the quality of their basestock is occasionally questionable. So with that being said, it seems like you would need to do a virgin analysis on each and every case of oil you are going to put in your engine and then do your used oil analysis to determine your actual wear rates. To me it seems kind of crazy to spend at least 50.00 (or more if extending OCI) for analysis and another 30-40.00 in oil for a change to show what? maybe a change of 10 or so PARTS PER MILLION! change. So added to the possible change in formulas, basestock, additive packages, your driving styles, temperature changes, miles on the vehicle, number of starts, may vary between oil changes leading to further skewed numbers. There are just too many variables to take into consideration to make an educated guess in the real world,, I guess when doing an analysis the numbers would have to be seriously alarming to justify anything. Anyone else see things this way?