E-M5 unreliable AF behavior

I'll add I have just tried what you suggest with my 45mm at F1.8.
I found negligible differences or none at all.

I'd suggest a brief experience with an SLR: compared to contrast detection systems, you'll find a 50% of shots off, at this level of detail. I mean all SLRs, even the most professional ones. Sorry, but pixel peeping is a sort of illness. You are just wasting your time. Be serene.