There's something weird going on here, @XRaySpeX I think you're right on the mark with the Home Hub not reporting the true sync, just checked the logs after this latest re-sync to see this:

18:17:40, 26 Mar. (92942.120000) DSL is up
18:17:37, 26 Mar. (92939.790000) DSL noise margin: 14.50 dB upstream, 9.00 dB downstream
18:17:36, 26 Mar. (92938.680000) DSL line rate: 888 Kbps upstream, 16521 Kbps downstream

16521Kbps, way off the 16.13Mbps shown by the Line Stats

Probably because of a 1024 issue.

I don't have access to the full source code and logic of the router or the BT speed test systems to give you the answer you really want.

Are you questioning whether the IP profile follows the sync speed immediately on WBC? Or just querying the value?

In reply to a post by matthewcl375:

16521Kbps, way off the 16.13Mbps shown by the Line Stats

16.134Mbps x 1024 = 16521Kbps

Post deleted by Chrysalis

Had you been following this you would have seen we had already identified a 1024 issue. Hence I am just questioning the sync value reported by the router, as from experience I trust the IPP value reported by BTw. That is why we are talking here about "True Sync".

There is no need for access to any source code; the logic can be reversed engineered empirically.

In reply to a post by matthewcl375:

18:17:36, 26 Mar. (92938.680000) DSL line rate: 888 Kbps upstream, 16521 Kbps downstream

Well, there you have it! The elusive "True Sync" we have been postulating .

In future, please always report logged sync along with router stats and IPP.

What is IPP now? 14.57 Meg?

Soooo close, it's:

Download speedachieved during the test was - 14.71 Mbps
For your connection, the acceptable range of speeds is 4 Mbps-21 Mbps.
IP Profile for your line is - 14.58 Mbps

Throughput is more than IP Profile - glad I went to partial LLU rather than 21CN WBC

In reply to a post by matthewcl375:

Download speed achieved during the test was - 14.71 Mbps

Don't trust this figure! It's higher than IPP (this time but not last), which is impossible.

You can trust IPP, but BTw Speedtester is notorious for sometimes getting throughput wrong.

Always use other speedtests, preferably TBB, for a reliable throughput reading.

Yep, I know all about that from my experience of 20CN, did exactly the same thing

It's kind of weird how a router can sync up at one speed, and then the next day sync at a completely different speed absent any changes in SNR Margin or Attenuation, the only thing that has changed is a 0.1dbM increase in downstream output power