Slow download speeds compared to sync speed?

[#1]

Hi,
After spending a few nights on chat support, testing everything up to the master socket, buying a new modem. Having the BT/openreach engineer for a half a day changing everything back to the cab and ports within (actually a nice helpful guy). I can say we are experiencing no faster download speeds.
We are on the 80/20 profile and the sync speeds can be seen with the attached file. We have 53336 down and 18924kbps up.  Actual speedtests do give us about 18mbps up but anywhere from 12mbps  to 35mbps down no where near the 53336kbps possible.
Is plusnet restricting/capping the download speed on this supposedly unlimited service? If no faster download is available I will be switching to a lower profile or at a push back to BT where we could hit 50mbps down easily on a old modem....

[#2]

Pn IP profile set incorrectly ? what is your BT wholesale IP profile ?
http://speedtest.btwholesale.com/

[#3]

Hi Interestingly today speeds have jumped dramatically. Now up to 47000Kbps down and 18000kbps up.
Sync speed has dropped slightly
System Up Time 21:03:47
Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN ADSL Link 486132 619369 0 58832 279406 00:48:52
LAN1 1000M/Full 1875761 1939070 0 29780 11430 00:45:06
LAN2 100M/Full 20:17:21
LAN3 Link Down --
LAN4 Link Down --
2.4G WLAN b/g/n 300M 363776 238999 0 5357 1943 21:03:47
5G WLAN a/n/ac 1300M 873444 634534 0 12943 5278 21:03:47
ADSL Link Downstream Upstream
Connection Speed 50955 kbps 18558 kbps
Line Attenuation D0( 15.0) D1( 35.4) D2( 54.8) dB U0( 2.8) U1( 29.0) U2( 44.3) U3(N/A) U4(N/A) dB
Noise Margin D0( 5.9) D1( 5.9) D2( 6.0) dB U0( 8.0) U1( 6.0) U2( 6.0) U3(N/A) U4(N/A) dB
IP profile has now changed;

1. Best Effort Test:  -provides background information.

Download Speed
47.76 Mbps
 
0 Mbps 49.32 Mbps
Max Achievable Speed

Download speedachieved during the test was - 47.76 Mbps
For your connection, the acceptable range of speedsis  34.53 Mbps-49.32 Mbps .
Additional Information:
IP Profile for your line is - 49.32 Mbps
2. Upstream Test:  -provides background information.

Upload Speed
15.46 Mbps
 
0 Mbps 20 Mbps
Max Achievable Speed

Upload speed achieved during the test was - 15.46Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps
Now these figures I can live with guess the profile has been reset or changed to a higher band, a bit of a shame no communication from PlusNet over two weeks to let me know what was going on.
Lets see how stable this will be...
Thanks

[#4]

Just to add; your profile has been set correctly throughout the duration of the fault raised. Hopefully it stays stable for you.