I can only apologise for all the mis-information that is knocking around. I think you've been trawling the boards long enough to accept there's a massive disparity between good and poor engineers. Add to the mix the constant threats of 'Performance Plans', which ultimately lead to being managed out of the business, and I can't really blame the engineers for doing what it says on the tin in regard to their test results.
There is NO mandate on
Broadband Faults that says if all the tests pass, we don't do anything else. If it's a
PSTN fault and has been raised as a CDTA (Conscious Decision To Appoint) task, then yes, we run the tests, utilise QLT on the landline and if all is OK we then leave and TRC (Charge) the ISP.
I put the blame in various camps, poor training, incredibly short 'Buddying' periods post-training, management emphasis on productivity, awful ISP front-desk knowledge of DSL ………… and ……… EU's who are anal about the tiniest of movement in their circuits performance.
I admit to bull-shining one EU in particular on my patch, who raises faults just for the company, I'm sure ?!
TBH, the whole kit and caboodle (from ISP, though Openreach to the EU themselves), carries vast swathes of confusion dependant on the knowledge and capability of the individual. Obviously, everyone on this forum is an expert, myself included, so such things wouldn't trouble us.
I wouldn't wish to guess on your expected speed. There's lots of calculations take place to give the estimate, cable poundage, CAL, perceived X-Talk ……… and it's only an estimate to the DP. I will say, that
generally on a normal 0.5mm copper line, that full synch is achieved up to
approx 300mtrs from the Cab, then tails off from there. I've highlighted the terms as I don't want any comeback from someone who know someone, who get full synch at 500mtrs. I'm just generalising.