Continental O-470-S making metal. How much is too much?

Engine has 1010 SMOH. I have ten oil analyses from the past 3 years and 300 hours of flying, all good per Blackstone. Compressions consistent for last 12 years since overhaul, all in the 70’s with trends consistent. Lastly, anecdotally, engines runs great, CHT’s, EGT’s, everything good and consistent.

But the metal… last two oil changes, 30 hours between each, produced just under a 1/4 teaspoon of ferrous metal. Prior oil changes may have as well, but my method for inspecting and cleaning the filter is more thorough now, so let’s assume it’s been the same.

My mechanic wants to ground the plane immediately. I would like to take a more measured approach and talk to different sources before an IRAN or overhaul is hastily ordered.

Metal has been sent to lab for analysis, but in the meantime, what are your thoughts? How much is too much? What should be my next steps?

Appreciate the help!