But the line has been completely stable with upload running at 1.6M, so DLM didn't need to fiddle and make it so that I cannot sync my upload more than 0.8M.
I keep aiming to respond here, but the goalpost keeps moving...
In the original post, you said that DLM hadn't actually intervened, and hadn't actually reduced your speeds. The only evidence you had was the output from tests by AA, but your line was still running as though DLM hadn't done a thing.
Now you say that you cannot sync at more than 0.8Mbps.
Which is it?