Could this simply be because of Interleaving?
No - your line isn't Interleaved as such. Your line has
G.INP. Traditional
Interleaving causes Delay. Your Delay is 0 - so no additional latency which is associated with Interleaving.
INP 50 is G.INP
INP 3 - 4.5 uses Interleaving with Delay.
Whilst G.INP does use a tiny bit of Interleaving, its not using it with RS encoding to add overheads. I was able to clearly see from the first set of stats that you do not have traditional Interleaving applied for the reasons explained by ejs, because the actual sync and max sync were similar figures.
As far a the DLM is concerned it doesnt call this Interleaving in your DLM line profile and class it as
retransmission.
Could the Interleaving be enabled because of some issue at the Cabinet or Exchange?
No.
Aside from the fact that you have G.INP and not Interleaving.. its applied on individual line characteristics.
Your line is on the standard profile. A DLM reset wont make things better.. it will make things worse, because you will then actually go into a period of having old style Interleaving applied.
I am just trying to find out the reason why my line was capable of an Attainable Rate of 93504~ Kbps but is now (supposedly) only capable of 68376~ Kbps and seemingly keeps degrading.
Unless there is a physical line fault - which would show other symptoms.. then it is likely to be crosstalk.
Mine started at ~110 Mbps.. its now only capable of 72Mbps or ~67Mbps when interleaved.
Your line will have several crosstalkers to varying extents, we only tend to notice the large ones. Although rarer, there's been a couple of people on this forum who have taken >20Mbps in a single hit from one disturber.
