Disappointing speeds from Extra upgrade

[#1]

On standard Fibre I was getting 38/10, until my upload was reduced to 2mbps. I then upgraded to Extra, as couldn't live with the slow upload. From memory it said the estimated download speed was ~ 50mbps, and according to my unlocked HG612, it is syncing around this speed (I think), although the bearer downstream rate says 45mbps.

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 12295 Kbps, Downstream rate = 50124 Kbps
Bearer: 0, Upstream rate = 12425 Kbps, Downstream rate = 45190 Kbps

Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3959)
Medley Phase (Final) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3959)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 12295 kbps 50124 kbps
Actual Aggregate Tx Power: 7.6 dBm 13.7 dBm
====================================================================================
VDSL Band Status U0 U1 U2 U3 U4
D1 D2 D3
Line Attenuation(dB): 8.1 32.7 48.0 N/A N/A 15.3 39.4 61.1
Signal Attenuation(dB): 8.1 31.9 46.9 N/A N/A 20.6 39.1 61.2
SNR Margin(dB): 6.2 6.2 6.1 N/A N/A 5.8 5.8 5.8
TX Power(dBm): 0.6 -10.3 6.5 N/A N/A 11.0 8.0 6.3

The actual speeds I'm getting now are 41/10 though, so the download speed is barely any faster than before. I just wondered if anything can be done to improve this at all?

The reason I think my line is capable of more than 41mbps is that a few weeks ago, before I upgraded, my download speed mysteriously increased to about 51mbps for about 6 days, and didn't drop at all during that period, so I'm fairly sure my line is capable of that. 

After the Extra upgrade though, it dropped down to 41 pretty quickly, within a couple of days I think.

All tests have been done over ethernet, by the way.

Thanks

EDIT: Just found some line stats from my modem, which I took when I had my temporary, mysterious speed increase a few weeks ago, showing that it was definitely syncing at >50mbps then:

Max: Upstream rate = 12803 Kbps, Downstream rate = 51572 Kbps
Bearer: 0, Upstream rate = 12848 Kbps, Downstream rate = 52790 Kbps

[#2]

Looking at your Signal to Noise Margin there is currently not much room for improvement. The higher speeds were mostly likely due to the last re-sync occurring during a period of higher SNRM.

What does BTW Checker state your line is capable of?

[#3]

Thanks for the reply. Here are the results from the BT wholesale checker. Looking at those, it sounds like i'm within the expected range, just right at the bottom of it?

Featured Products

Downstream Line Rate(Mbps)

Upstream Line Rate(Mbps)

Downstream Range(Mbps)

WBC FTTC Availability Date

WBC SOGEA Availability Date

Left in Jumper

High Low High Low
VDSL Range A (Clean) 53.8 40 13.3 8.6 -- Available -- --
VDSL Range B (Impacted) 40.9 25 10.4 5

[#4]

Well I did some more research on this myself, to better understand the reference to the 'impacted' speed estimate.

Found this interesting article which explains that the impacted estimate is the worst case speed taking into account the effects of crosstalk, which can increase as & when new VDSL connections are set up in the cabinet.

So, as my speed is right at the bottom end of the expected range, I assume that a few people on the same cabinet as me must've signed up for FTTC in the last few weeks.

Plusnet staff - please could you advise if you think there's any mileage in me raising a fault ticket for this, given that my download speed is barely any better than when I was on 40/20, and my upload speed is actually slightly worse now (I used to get 10-11mbps up, now I'm getting 8-9mbps.

Many thanks