The 320 IS much more of an issue in the flare with F3 than the 321 in F3. Don't try to hold it off. I find closing the thrust levers at 25R and a tiny little flare about 15R will see you right. If you use a Flap full flare with F3 you will float along at 8 feet!
That's also my experience.
As a matter of fact, the A321 wing trailing edge is different from the rest of the family -Airbus has added a few inches to the chord, therefore on the flap dimensions. The result is a somewhat "flatter" attitude during the approach than on a 320.