I think I understand all the values except the significance, if any, of the change in attainable from 78 to 83. Maybe it is just a quirk of how the values are estimated in the two states?
I don't profess to understand why, but we always see such a difference whenever interleaving is applied.
It would appear to be physically impossible to ever achieve the higher speeds.
The only exception to this rule is when a connection resyncs at a particularly quiet period, when sync speed gets 'close' to attainable rate.
On those occasions, we often see sync speed maintained, but attainable rate becoming lower than sync speed when noise increases i.e. when SNRM reduces, currently below 6 dB in the case of VDSL2 connections.
Here's a recent example from my connection:-
Max: Upstream rate = 4027 Kbps, Downstream rate = 21148 Kbps
Bearer: 0, Upstream rate = 4516 Kbps, Downstream rate = 22271 Kbps
DLM clearly didn't like that after approximately 24 days as the connection resynced & ended up like this:-
Max: Upstream rate = 4216 Kbps, Downstream rate = 21268 Kbps
Bearer: 0, Upstream rate = 4245 Kbps, Downstream rate = 18858 Kbps