The following paragraph, extracted from a Transport Canada special condition, may give a clue:
Additional landing information giving the distance between the runway location of the landing reference aid and the runway stopping point must be provided. This information is not required for London City Airport (EGLC)
My understanding of this requirement was that it is intended to cover any airports where the guidance, for whatever reason, does not bring you to a "normal" position on the runway, but rather some other nominal location. As a consequence, distance required data based on a "normal" threshold crossing height, an allocation of air distance and ground roll onto the LDA might not work. In such a case, you'd use the data required by this para in combination with the "distance beyond glideslope" to work out whether you ought to be landing or not.
The data mentioned in the first post potentially describes a non-standard relationship between the glideslope intercept point on the runway and the threshold, meaning the normal distances might not work. the data required in quoted para would allow the use of the available data for a proper landing assessment.