My apologies; I misread it. I presumed you had already made to move back to Amsoil.
These results are hard to argue with; fantastic numbers nowhere near condemnation on any level.
As just a point of conversation, could Amsoil do "better"? Possibly. But it would be really hard to do "better" than this "near perfect" result. When you get data this strong, it's hard to turn away from the truth; this combo flat works. Now, it's entirely possible that another brand of oil and filter could do this well. You'd have to test it and see. But the wear in this sample is telling you that the extended OFCIs are not harming a darn thing; EVERYTHING is in order here. This fluid could easily be still in use. Would it go 50k miles? Maybe ... maybe not. But it could certainly got close to that. You'd not really know if the wear rates would escalate or not, causing the Fe ppm to accelerate or not. But there's a reasonable mantra here to say that at 26k miles, you were approximately 1/2 way to the Cummins limits. And do NOT, in any manner, consider the condemnation limits that Cummins sets to be detrimental. It's not like the engine is going to puke and die if it sees 100ppm of Fe, or 3% of soot. Those are limits that Cummins set to trigger an OFCI for the
continued safe operation of the engine.
Those limits do NOT represent where damage happens; they represent trigger points for an OFCI that assures safe operation is nearing it's end. But it's not AT it's end. So it is VERY conceivable that 40k, 45k, perhaps 50k miles is doable here with this combo you've got.
On this combo of the Fleetguard and Schaeffers, I'd run UOAs every 10k miles, and track the wear rates and contamination, etc. If you're into extending the OCIs, (which you apparently are), then use the data to your best advantage. Trust the data and what it tells you!
The grand irony I see in some BITOGers actions is that IF they use UOAs, they will often OFCI based on their own condemnation limits; limits that are artificially low and resoundingly too conservative. When a UOA clearly shows a problem, they will act on it. But when a UOA shows everything is desirable, they will still OFCI based on their "intuition" and not continue the OFCI based on the data. It becomes an act of hypocrisy; they trust the data when it shows something is wrong, but they don't trust the data when it shows everything is right. I'm not saying this to taunt or otherwise deride you. It's just human nature to always want a "perfect" situation for something we care about and have paid a lot of money for. But the DATA you pay for is telling you that you're only about 1/2 way to condemnation as Cummins sees it. And is it your position that you know better than them?
Cummins does not set condemnation limits at the danger point; they set them PRIOR to the danger points. So it's perfectly acceptable and even desirable to run UP TO those limits if you're into OCI extensions. If not, then why are you doing UOAs in the first place? UOAs are not supposed to be toys; they are tools. If you know/understand how to use the tool, then it's silly not to do what the tool tells you is safe and pragmatic. Again - I'm not lambasting you here; that's not my intent. Rather, I guess I'm preaching the gospel of UOAs and their true nature of use, to not just you but anyone who listens with an open mind.
I applaud how far you've gone; you're going where few are willing to travel and you are to be commended for it!
Just know that the data is telling you that you're actually only about 1/2 way to the end of a perfectly safe journey.