Current line speed wrong...as always

[#1]

Is there some technical reason why the 'current speed' on https://portal.plus.net/my.html?action=data_transfer_speed rarely stays the same as
the BT IP Profile.
My current line speed is shown as 60.8, but the current profile is "IP Profile for your line is - 62.13 Mbps".
A week ago I was connected as 73 mbps after 87 days without a disconnection, I had two. The first pushed up the profile to 73 (which I only
discovered after the modem was rebooted, after a power cut), but then after another few days, the modem rebooted itself & dropped to 60.8.
What is annoying is that Plusnet's system does not update automatically without me posting on this forum. Why is this????

[#2]

it usually does albeit slowly

[#3]

I found https://community.bt.com/t5/BT-Infinity-Speed-Connection/questions-and-answers-on-DLM-sync-speed-and... helpful
It seems the fttc kit favors keeping a stable line vs the fastest. 

[#4]

Finally updated - took two days.