I always get 800+ kbps lower than my IP profile

[#1]

Why is this?
DownStream Connection Speed 17218 kbps
UpStream Connection Speed 984 kbps
PPPOA
IP profile 15MB on plusnet and 15.2MB on BT
Speedtest -
Thats like a 19% over head =/
I though it should be more like 10%
not complaining just curious would a 16MB profile help on plusnets side?

[#2]

I make 15/15.2 about 12/13% less than 17.2 Mb/s.

[#3]

Or , to look at it another way, you're achieving a download around 94% of your (PN) profile which should be around the maximum rate you would expect so not too bad really.