FTTC - Trial Queries

[#1]

Well I'm getting towards the end of my first week with good and not so good results. I have a few questions.
My upload does seem to have stabilised around 16000 kbps (this is about 10 times faster than my old 40/2 profile).
The download is another matter, I have seen peaks on the speedtest systems around 72000 kbps, although this is very rare (tried at various times and days, I constistently got 36000 on 40/2) tending to be around 20000kbp.
1) Watching the download bar for large files it would progress in stops and starts. Looking at the download graph for large files it tends to be very saw toothed. Is this data shaping?
2) How do I find out if my exchange is overloaded (POLESWORTHEM) could that be causing the problem?
3) Am I being over optimistic to expect 72000 kbps all the time (or at any time!!!!)?

[#2]

1) Could be. Have you looked at the information here: http://www.plus.net/support/broadband/speed_guide/download_speeds.shtml ?
2) http://usertools.plus.net/exchanges/
3) Yes - unless you are also paying for the Pro Add-On which gives full speed on all protocols at all times. https://portal.plus.net/AddOns.html You can see the affect that has if you look at the Pro Add-On table in the first link I gave.

[#3]

Well checked the exchange and it is Green. So that can't be the problem.
And I am paying for the Pro option.
Could the plusnet infrastructure be overloaded then?
If there is no reason for the lack lustre performance then 80/20 doesn't really benefit me!!!

[#4]

What does https://portal.plus.net/my.html?action=stable_rate say for your current line speed?

[#5]

This is what it returns.
Estimated line speed:Not recorded (service activated before we introduced estimates).
Current line speed: 20 Mb

Not sure what that means I just did a speed test and got 48000 kbps download. (Did 15000 on next test  )

[#6]

That means it's not Plusnet holding you back. 20 is a special setting for Fibre that lets the line go at whatever speed it can.

[#7]

OK thanks. I did get 74/16 at 5am this morning. It does seem a little better tonight at 30/16.
Suppose I shouldn't complain, when I was a lad high tech was 2 tin cans and a piece of string 

[#8]

Strange how some people's speed varies so much, I've read several accounts of people on 80/20 only getting speeds of around 30-40Mbps most of the time despite having profiles in the 70s. My actual speeds are consistently around 61/17 at all times, and I'm not paying for Pro.