When is a new FTTC install considered failed?

[#1]

Hi all,
First time poster just looking for some thoughts on my situation.
FTTC install on 04/12/15
Initial estimate of 21.6 - 14.7 Mbps
Engineer confirms 21.6 Mbps estimate
First seen sync at 16000Mbps falling over the next 10 days to 11000Mbps sync
Constant upstream rate of 500kbps
Line Attenuation has increase by around 10 units after FTTC install.
Considering this 'upgrade' is becoming slower than the previous ADSL2+ install on same line, can this be considered a failed install?
Tony

[#2]

BTW Speed test 06:40 0n 15/12/15 -
Download speedachieved during the test was - 9.59 Mbps
For your connection, the acceptable range of speedsis 8.47 Mbps-12.11 Mbps .
Additional Information:
IP Profile for your line is - 12.11 Mbps
Upload speed achieved during the test was - 0.41Mbps
Additional Information:
Upstream Rate IP profile on your line is - 2 Mbps

[#3]

Telephone number:
    01730******
Phone exchange:
    MIDHURST
Estimated line speed:
    21Mb (This may vary between 14.7Mb and 21Mb) - Checked on 2015-11-19 21:05:00
Current line speed:
    11.8 Mb

[#4]

were those tests wired or wireless - it is the upstream number which looks odd

[#5]

All wired. Straight through a Plusnet  supplied Hub One and also tried with a TP-Link W9980 both directly into test socket. NO OP modems involved in this install.

[#6]

Hi there @misterTony,
I have looked into your line for you. I have checked your line today and can see that your line is estimated to be 1.7km from the cabinet, and therefore, the speeds are likely to be lower than the original estimates given.
I can see you have raised a fault and our Faults Team will pick this up within 72 hours and look into this, but unfortunately it is possible this will not be able to be improved. I'm sorry about that.

[#7]

Hi Mel,
Thanks for picking this up.
That doesn't explain unfortunately, why the initial sync speeds were so much higher and the subsequent drop off.
Neither does it explain how my Line Attenuation has jumped since the FTCC install.
But I shall wait for your faults team assessments and take it from there.
Would PN consider a roll-back to ADSL2+ should this not be resolved? #justathought
Tony