Profile, is this correct?

[#1]

Saw this comment over at another forum, is this correct -

Quote

Plusnet internal IP profile shaves 1-2Mb/s off max throughput. http://forums.overclockers.co.uk/showpost.php?p=26711961&postcount=13

[#2]

Hi PLan,
You will see a difference in speed on both the sync and throughput of the profile on the account side as the overheads need to be taken into account.
With Fibre you would see  a formula of ( sync speed * 0.967 = profile speed )
With ADSL2+ you would a formula of ( sync speed * 0.882 = profile speed )
So while there will be a slight difference, it isn't as straightforward as the quote you provided in your initial post.