Effect of interleaving on FTTC?

[#1]

I have FTTC, on the 'value fibre' package, i.e. "up to 38mb/s".
I saw from my router log that there had been a series of internet disconnects over the weekend. I don't know if this was just the IP connection or if the underlying DSL connection also had problems. (How can I tell? I don't have an unlocked modem.) So I ran some speed tests, mainly using speedtest.net on the same server I've used previously.
Ping has gone up from 10ms to 25ms, and download speed has reduced from 36.5mb/s (very little variation over several months) to 34.5mb/s (very little variation in the past couple of days). Upload speed seems unchanged at about 8.6mb/s.
Plusnet IP profile is unchanged at 37mb/s, and BT IP profile is also unchanged at 38.72mb/s.
So, are the changes I'm seeing the result of interleaving applied to the line, or could they be due to something else? And, if the former, will interleaving eventually be removed if the line now stays stable?
(I'm not worried about the change. I'm not a gamer, so the ping change doesn't matter, and there's very little practical difference between the download speeds in normal use. I'm just curious.)
Graham

[#2]

Hi Graham,
Interleaving will be what has caused your ping rate to have jumped, it may have had a slight impact on your speeds but generally, most people wouldn't notice.
If your line remains stable, Interleaving will automatically be removed. It's very difficult to see what caused any disconnects, generally there have been a large number of them, we ask our customers to carry out a couple of checks to rule out internal equipment, however, in this case, it looks as though the line is stable.

[#3]

Thanks, Chris.
I've no idea what caused the disconnects. There were 16 of them between 13:25 on Saturday and 09:39 on Sunday, then another one at 03:03 on Monday, after which the connection's been up all the time.. I'm 99% sure it wasn't anything to do with internal wiring as I haven't changed anything in that time. If you say it looks like the line is stable then the problem was probably at the IP level rather than with the DSL Let's hope it was just a blip and that the interleaving will at some stage be removed.
Graham