What if your speed doesn't fall into these two ranges? Mine doesn't.
I've had a look at my profile (65) and it falls outside the ranges quoted for me. Do I need to contact the helpdesks or get BT to look at my line?
The dslchecker is an estimate of what your line might be able to achieve if everything was perfect. That means, as all estimates do, that some may get more and some may get less. It is not a promise of the speed you will get.
If you are getting 65Mbps I doubt that BT or Openreach would do anything to try and improve that but you could always ask.
Here is an explanation of what your IP profile is and why it's more important than an estimate.