Then the answer you’re looking for is the Airbus has a Trim Tank Transfer system which controls the A/C C of G.
At FL255 on the way up fuel is transferred aft (depending on a few conditions) then as fuel is burnt from the fwd tanks fuel will be transferred fwd depending on the C of G.
If any fuel remains in the aft/trim tank on the way down it'll be transferred fwd at FL245.
Now the -400 just has a specific order as to what fuel is to be used from what tanks, Assuming full tanks the order goes CTR tank to a certain amount then the STAB tank, then back to the CTR until it's empty [or the low Press lights come on, usually around 900kgs (which the scavenge or jet pumps can finish off)]
Then the I/B tanks, plus at a point the reserves transfer into the I/B tanks so this fuel is burnt until the I/B equal the O/B at which point you select Tank to Engine.
So the simple answer is the Airbus uses Fuel for C of G control and the -400 doesn’t.
Hope this helps.