Moisture retention is controlled by 4 factors (please search for flocculation, and 2-3 other posts where I have posted about moisture levels specifically before): 1) set time before cut 2) Cut size of curds 3) temperature 4) Stir schedule. For mozz, the handling also makes a difference, but not between dry mozz and moist.
I suspect you are not being consistent with your curd size, or somewhere else and are losing too much moisture before fusing the curds. Also, you may be slightly overacidifying based on your texture description and citric amt (depends on milk, hard to say offhand).