In the meantime, Tony sent me a copy of the Hlog data as uploaded from your connection.
If you look closely at your locally generated graphs, you will see that they creep into positive values at tone 16.
Here's the raw data:-
0 -96.0
1 -96.0
2 -96.0
3 -96.0
4 -96.0
5 -96.0
6 -96.3
7 -96.3
8 -0.8
9 -0.8
10 -0.8
11 -0.8
12 -0.8
13 -0.8
14 -0.8
15 -0.8
16 0.4
17 0.4
18 0.4
19 0.4
20 0.4
21 0.4
22 0.4
23 0.4
24 -3.3
25 -3.3
This is a bit of an anomaly as Hlog is a measure of attenuation, therefore values should all be negative.
This happened briefly to Kitz a long time ago (Zyxel modem), so I amended my programs to cope accordingly.
I have asked Tony to check if he might also need to do the same within MDWS.