[Sephiroth]

For what my opinion is worth, it would be worth seeing your upstream/downstream power and SNR levels. The BQM is indicative of an upstream problem (which always screws downstream), possibly caused by upstream noise.

That might be due to a loose cable into your Hub; you could check with your neighbours because if they have very high upstream power levels, then there is a common fault either at you local cabinet or the launch cabinet et or the optical node.

So, please post your levels.