For Fe you should expect xx PPM per 1k miles whether you do 3k OCI or 10k.
Apparently.... they don't always (logic says they would)
Read the link I posted above
So, aside from that the test was done in 2003 and they didn't ever post up their completed analysis... (also their graph doesn't seem accurate to me?
In terms of wear metals in the UOA, one would have to break it down to PPM/1k miles to get an idea if there is an increase/decrease or linear accumulation. To be honest, I wonder if it's even reasonable to conclude it's worth comparing the ppm results in 1k incredements between different samples sent to Blackstone? It's a $25 spectrum analysis anyway, right? More so to give a ballpark figure than exacts? So, not conclusive by a few ppm off.
I'd be more concerned with their findings of the oil thickening up; which is an older formulation of course, as to evidence of extending too far in that run. Anyone with results of it going up an entire grade in our UOA section, etc? I vaguely remember that guy in Philly posting his UOA with Amsoil 0w20 or 5w20 and it was shot due to 1/2 mile commutes over the winter.
Some oils are known to have ran with higher Fe numbers trending; looking squarely at M1 of those years in some engines, so it's not surprising. Where as Amsoil proves the opposite here, while at the same time their reported UOAs indicate the oil was due to be changes at 9k.
Note that when the TBN was basically finishing up at 9k miles they added 1 full quart and it boost to 2.4 TBN by the 10k report and immediately fell lower than the 9k reading once it reached 11k? That OCI was effectively over at 11k but they kept pushing it and THAT was when the Amsoil began to increase in Fe. So, given the "room" to top-off with an entire quart and their findings the OCI should've been capped at 11k for repeatable results (given the makeup oil added).
An entire new study with a couple apps/engine types; such as two of each type, with modern oil formulations could run similar tests to contrast with one another subjectively while objectively viewing their own results due to the differences in real world operation between the two (2 DI engines vs 2 engines that are easier on oil for example).