Not an Airbus man, but two comments of a general nature.
(a) the other consideration for fuel usage programming is that we prefer to keep fuel in the outer wing panels for bending relief - another input into the walnut moving.
(b) For GC <25% add 2 kts to Vls ... Forward CG (<25%) increases landing distance by 2% on a dry rwy and 3% on wet or contaminated runways.
Characteristic stall. Forward CG (at higher weights) produces the maximum stall speed which then goes into general speed and distance calculations. It appears that the Airbus has adopted two paddocks to get a general advantage with the forward penalty being a higher approach/landing speed and, naturally enough, a modest distance penalty.