An aspect not mentioned applies definitely to the local FTTC cabinet and probably to most in the larger surrounding area.
The local PCP apparently has 287 lines through it.
The FTTC cabinet is a Huawei, capable of taking 288 upgrades, absolute maximum.
It apparently has all six DSLAM Cards in it; but not 100% certain.
These connect to a back-plane which can take up to 288 Filter/Links, superficially looking like miniature circuit-breakers or fuses. The back-plane is the main component in the right-hand side of the FTTC cabinet, with the linking cables to/from the PCP rising up from directly below.
Virtually everything else is on the left.
These Filter/Links are essential parts of the circuitry, in providing VDSL.
When first released for service in March 2014, only the first two sub-groups on the back-plane had the F/Ls fitted, allowing a temporary maximum of 48 VDSL Upgrades.
About May 2015, another 48 F/Ls were fitted, taking about 5 minutes as I spoke to the person actually doing it. (He had another 20 to 25 cabinets to do in the wider area that day, asking directions as to how to get to one, as he was unfamiliar with that area, about 10 miles away.
This would allow a new temporary maximum of 96 upgrades.
About May this year, there was an upgrade being carried out at the PCP; and that person told me that it was the 64th, there already being 63 carried out over the previous 26 months, less than 3 per month average.
So you may be encountering one of those temporary maxima, rather than the absolute total for your FTTC cabinet.
I don't know how you can establish which version you are encountering.