Only Broadband trained engineers have 'permissions' to request access. Most wont do so, as there is an NGA Helpdesk we can ring to get relevant information.
Being pedantic but also quoting our 'regs' , if the engineer performs a PQT to SIN349 and there are no issues, coupled with a 'Synch and Data' check that reveals there to be no errors. Then that's job and knock. Comparing 'Baseline Data' and the effects of crosstalk are not under our remit, as we don't guarantee speeds.
Obviously, this is a generalisation and it depends on the job at hand as to how 'Faulting' is carried out.