First the background: Airbus gives 3 landing distance tables, "manual/manual", "manual/autobrake" (FCOM 2.03) and "autoland/autobrake".
"Manual/manual" is the minimum landing distance based on certification flight tests. You arrive over the "screen" (50´) with Vref (Vls), retard the thrust and rotate the aircraft along a constant flight path resulting in a touchdown speed of Vls minus 7-8 kts and a relatively high pitch attitude. Derotation is positive and max brakes are applied without reverse.
"Autoland" includes the addition of the A/THR +5kts and that is why there is a difference between the FCOM 2 and QRH values.
Assuming that all systems work as per design the only variables affecting landing distance are landing GS and residual thrust (+ some wind effects during ground roll).
This is why Airbus recommends retarding thrust at 30´/40´and before the retard reminder, but....
Line pilots are reluctant to do this 
. Many prefer to keep the (auto)thrust in , sometimes even to touchdown, with a baloon, a 3-pointer, a prolonged flare or firm touchdown and excessive landing roll as the result. And this is not only a French problem; the West Coast jocks are even worse, if anything.
During countless base-flight landings with pilots having between 100 and 20.000 hrs total stick time I see a clear tendency: The thrust is retarded too late for an easy landing (old hands and Boing/MD to Airbus converts are most pronounced).
Once they retard as per FCOM and make a smooth rotation the whole thing falls into place and the landing becomes simple. The exception is if you have a lot of ballast concentrated in the rear of an empty aircraft (which is often the case during base flights), then the bird becomes more responsive and does not require a positive flare, but this configuration is rare during normal ops.
There are a few Airbus diff´s: Early A320s require a more positive flare, A321 - having a different flap slot - require less rotation and 330/340 settles nicely with 40´ retardation and a smooth rotation.
But is late retard a No-no? If the actual headwind is stronger than the FMS entered value GS mini may give too small an addition. If the wind is gusting greatly or downdraft is present. Then is may be prudent to delay the retardation at the expense of longer landing, but dont do it as a routine. And not in tailwind....and not with Conf 3 or less.
An operator had a serious problem with hard landings on a particular (non-airbus) type. I made a FDR study of the hard landings and
all had a touchdown attitude of 4 dg or less. It turned out that the pilots had been taught a "power-on/no flare" technique ever since the CFI converted from straight wing props to jet some generations ago.
You may have heard that "this new aircraft require a totally different landig technique"....Bullocks! I have flown supersonic deltas to LSAs and a lot in between and the fundamentals are the same (except those with boundary layer suction and blown flaps).
Remember: An aircraft is an aircraft is an aircraft! Chop the thrust at FCOM value, rotate a few degrees (typically from 3 dg ANU to 5-6 dg ANU depending on CoG) and wait for the kiss. Even if the flare is a bit longer than you are used to, the stopping distance is not affected much,
if you got rid of the thrust passing the threshold.
Next time in the sim, ask your friendly TRE if you can practise a few landings (yes...I know..but anyway..).
Happy landings!
Capt T.