BT Profile on ADSL2+

[#1]

Currently I'm synching at 19360/1078 as per my router.This gives a calculated profile of 17.07Mb . PN are showing a current line speed of 17 Mb and I'm getting speed tests of 16 -16.7 Mbps -all good so far............... BUT..... when I use the BTW tester it is giving dowload and upload speeds greater than the shown BT profile eg this morning actual speeds 16.37Mbps/ 0.93Mbps vs profiles of 16.03Mb/0.83 Mb
Anyone else had a similar experience and did it correct itself?

[#2]

This has been reported before and as far as I know there hasn't been a satisfactory explanation other than "it is just one of those odd things and no speed tester is perfect"