DLM and IP profile changes

[#1]

Would someone be kind enough to explain why my IP profile has been reduced this morning from 3Mbps to 2,5Mbps when the connection speed still falls within the 3Mbps range? Yesterday my connection speed was 3776 Kbps profile 3Mbps, to day connection speed is 3680 Kbps.
Kitz shows me that connection speeds of 3424-3968Kbps fall into the 3Mbps profile.
I also cannot work out why the connection speed changed as my SNR has never fallen below 5.6 lowest upto 6.6 highest, which to me seems absolutely fine and stable. DLM just seems to get involved for no apparent reason.

[#2]

Does your router log tell you how many times the connection dropped and to what speeds? Presumably there was a lower speed between the 3776k yesterday and the 3680k today. Or there could have been a lower profile from a few days ago that only just now reached Plusnet.
The DLM is probably not responsible for the drop in connection considering you are still connected at a similar speed. The DLM wouldn't increase your target SNRM just to decrease it again a few hours later.

[#3]

ejs: I don't know if my Billion 7800n has that capability regarding reporting all details you ask. I have an Event Log which only shows via telnet, the "live" events while online and this is through DSL Stats software programme.
I attach 2 snapshots of the DSL STats info. The first is from startup on 26April which shows my DSL Uptime as 1 day 12 hrs, and this mornings Uptime (27April) as 12hrs, so something happened at around 8pm last night when i was not active onlone.
The question as to why my Profile should drop is still confusing me as even the current connection speed fall inside the 3Mbps profile.

[#4]

@jjaycee1
The connection is looking fairly stable at the moment so I've submitted an SNR reset.
I'll be checking back after an hour or so to see if I can adjust the speed profile.