differt types of displaced threasholds
The licenced runway might be one length, the displaced threshold for landing in one direction might give a second length, and then the displaced threshold for landing might give another.
For example look at Farnborough.
The condition of the surface is also relevent, the unused tarmac might be bad condition, and as such usable for an accelerate STOP, but not approved for regular use.
I have also seen raised runway end lights marking the displaced threshold.
Thats all folks...