Why on earth would your ISP reduce your speed if you were thinking of leaving?
I might of been drunk when I wrote that part about my isp 
I can't remember what I meant there hahahaha
Oh! I remember now! I was probably thinking at the time, maybe after getting those max 67 speed estimates, the live database sent a signal to the DLM on my cabinet to slow it down to 67.......
The more likely scenario here is your line check was reporting what your line
should have been syncing at based on the current stats, but if it hadn't resynced in a while you would still be connected at what it previously could handle before the crosstalk you are now subjected to.
Particularly if you are on an ECI cabinet, DLM wont allow you to sync lower than 6dB SNR, your line had probably drifting below this so the re-sync meant your speed reduced.
Over the last couple of years my own line has slowly reduced from 79Mbit to 66Mbit. That's just the way it is with more and more people getting VDSL. I know around here there used to be a lot of mobile hotspots, as they have changed into Sky and Talk Talk, my speed reduced, showing the clear indication of what caused the extra crosstalk.