The 'TDZ' (fixed distance runway markings) is not related to actual runway length, thus there is no relationship with the aircraft landing performance, which is based on the LDA and local conditions (LDR).
The TDZ should not be confused with, or replace the expected touchdown position.
I don't agree. With respect to landing distance, My Boeing FCOM says/said:
Air Run Distance from threshold to touchdown is associated with a flare time of 7 seconds.
Therefore, it is quite easy to work out what the distance to touchdown the data is based on. 7sec at 200fps (120kts) equates to about 1400ft, or the roughly 450m markers. This applies in all cases, short or long runway.
Provided your runway is marked IAW ICAO, you will, beforehand, know where the 7sec point is WRT the markings. It is therefore easy to ascertain if you will/have touched down in the "TDZ".
For example, on FLYSMART as part of the briefing, you are well served to make note that we have 285 metre of margin should we miss the touchdown zone.
Since the performance touchdown
point is predefined by the regs (7sec), it does seem to me to be valid to acknowledge the extra 285 and use judgement as to whether you GA or not. Why would you GA on a long landing on a 3500mm runway? Because you know that the performance book says you'll need 1800m based on touchdown point of 7sec/1400ft, and if you float another 500m, you still have room up your sleeve (3500-1800-500). Not that I condone regularly landing 500m past the performance TDP!
I don't fly the A320 but I assume the certification requirements are similar (ie 7sec to touch). If the aeroplane isn't touching down by the 450m markers/point (~7sec), you're now eating into your predicted landing distance. This is all regardless of the LDA.