"It means that your line is most likely stuck in a banded profile. In this instance, on the DS side. If you could post your line stats, I can confirm this for you"
So was enquiring as to what confidence you could confirm its a banded profile. Nothing to do with estimating line length.
The questioning is a reminder that people will taken things like 'I can confirm' and believe you totally, so if you cannot be 100% certain better to qualify any comments.