The goal post moving seems at least partly an excuse to avoid work, surely enough was known to make the estimates realistic in the first place. My estimates are now on their third edit. Assuming that the lowest figures are the ones that matter when raising a fault things have changed a lot.
At sign up FTTC range B impacted 80 - 73 down
a year later 60 - 34 down
now 21 month later 50.6 -30 down