That CRC level is about 10/hour, which seems to be perfectly manageable - you're not likely to see much of an issue when you are browsing or downloading.
I recently went to non-interleaved, but on a rather better line. I went from 30 FEC per hour (and almost no CRC) to roughly 30 CRC per hour. My errors are very sparse, so each error that was correctable with FEC became a full CRC error without.
If your errors are spread out a lot, then the 85 million FEC errors could become 85 million CRC errors; if the errors occur in dense bursts, then this could reduce to, at best, 1.25 million CRC errors.
Over the 6 days, that would be a theoretical range of between 2 and 164 CRC per second.
However, the way the data is carried on the line means that 60 CRC errors per second is 100% failure, so you can't get higher than that. At the very best, you will be guaranteeing yourself (2/60) errors, or 3.3%, but probably rather higher.
In this case, I'd say the the FEC correction is doing its job extremely well. I would only turn it off if I was in a very experimental mood, and willing to accept that it might make the line unusable for at least a day, and then have a knock-on effect on the IP profile even after it was turned back on again.
And, unfortunately, turning interleaving off also turns off FEC.
Plusnet Customer
Using FTTC since 2011. Currently on 80/20 Unlimited Fibre Extra.
