Do you know how many cabinets they do a day? I'm guessing it's a simple config change for each cabinet, or maybe they do them all in batches in one area.
BT reported 45,000 lines per day; I reckon that means between 600 and 1,000 cabinets per day.
However, upgrade of the cabinet does not necessarily mean the line profile changes immediately.
It was 24 days between my cabinet upgrade (visible as a 10 minute outage overnight on a BQM) and my line profile changing. Not once, either before the cab upgrade or afterwards, did my line hit any of the old thresholds that would trigger DLM, so the change in line profile was a surprise.