BT dsl checker

On http://www.dslchecker.bt.com/ it gives two sets of figures for Downstream, e.g. for me:

Downstream Line Rate(Mbps): Up to 1.5
Downstream Range(Mbps): 0.5 to 2.5

Why the two figures / what's the difference between them?

My actual Downstream (from the homehub stats) is 1.688 Mbps, it used to be 1.8 something a while back though.


Thanks

For providers who just want to give an up to they use the first.
For those giving a range they can take the second.

It is just different ways of expressing the estimate, and there is always an uncertainty hence the various caveats on the page. Real driver is the attenuation on the line.