Calculating a perceived ROI based upon supposition as to how far a lube might last is somewhat dubious. You really don't know how far a lube would go until you actually try it. Set limits, run up to them, and only then look at the odometer. Use the UOA for it's true purpose.
I would say based upon the information that I have from my UOA stream, I have a fairly good grasp on how long a conventional oil will last in my engine and I do believe that MS5K would be EOL at 12K. For the synthetic piece, it is true I am extrapolating somewhat, but the numbers for lube life that I used are not completely unreasonable. I suppose time may tell on that part.
But there is a little used process that often becomes the better blend of a hybrid lube system. Use a good dino and bypass! The benefits of premium filters, along with the savings of conventional lubes, make for some of the best ROIs out there. As most of us know, oil really never goes bad, but it does get contaminated. Bypass cleans the lube to a much greater level than full-flow alone, so if the oil can stay clean, why does one "need" a syn?
Interesting concept, but unless I am totally off the mark, no filter combination can remove liquid contaminants (to do so would require it to be a miniature chemical refinery) and therefore no matter how well it removes particulates, the EOL will usually be determined by the reduction of additive pack or increase in acidity (at least I believe this to be true in gasoline engines). While I do not claim to be a SME on UOAs, it would seem that wear metals (which a bypass system would help remove) are not normally the reason for condemning an oil, but flash point, low TBN, high TAN and like are and these are chemical changes not necessarily physical ones. How does a bypass filter system help with this? No sarcasm here, I am genuinely interested in understanding how a bypass system increases oil life.
As always thanks for your knowledge!