I just threw some numbers together. BEFORE REBUILT was 11560km avg & Fe 28.7142857143ppm avg
That reading isn't bad at all & after rebuilding appears to be even better wear rate at 10000km & 22 Fe (Iron) albeit just one sample so far after rebuild.
But as you're seeing some viscosity increase I'm not sure on how all that works. Shaeffer's is darn good oil & 5w40 FS would get my vote over 15w-40 Semi-Synthetic based on your prior notes. Either way still not bad. Thanks for the post!