As noted in the response concerning your 'Jiro', the problem could be overfertilization or inconsistent water.  There are two other considerations:  your Hachiya seems to be a young tree, so for it to produce even three such beautiful persimmons is a remarkable event.  And, again, patience may be the best tactic.
The 'Hachiya' is also self fertile and is prone to producing parthenocarpic fruit, i.e., fruit with no seeds.  So even a 'sterile' tree can produce fruit.
The weather conditions last year caused numerous fruiting plants to drop fruit prematurely or to simply not produce fruit at all.  It was assumed that the cloudy, rainy weather during the bloom period deterred many pollinating insects from flying.  If similar conditions occur this year, consider hand pollinating the blooms.
LS