I've noticed than some native persimmons won't be as regular as most of the grafted cultivars. One of the reasons for this is that most named varieties were chosen because they had special attributes - and one of those attributes is generally that they are more reliable. I would say that maybe only 30% of my natives are as reliable as the best grafted trees.
As stated in the above post, shade can be a problem, even though they are more shade tolerant than apples. I will also say that persimmons react very well to fertilization. You might try that and see what happens.
This spring I topworked a native to Morris Burton from scions that someone gave to me, and the scions are trying to make persimmons this first year.