It IS possible to change the position of the number of hole instances. Just not automatically by default. In your Dimension Property, simply "Cut" X and paste it to your preferred location.
Its kind of a PITA that you can't make it do this by default, but at least you will get your desired results.
On a second note, I am just starting to play with hole callouts and am trying to customize my callout file. But I have kind of a side question regarding hole callouts.
In my drawing, I prefer to create a section view thru the holes and have the callout pointing to the hole in the section view. Currently, I use a note with a leader pointing to the sectioned hole. To keep my "note" hole callout somewhat parametric, I dimension the sectioned hole, link my note to these dimensions, then hide these dimensions. First, this is also a PITA to do. Second, there are limitations such as not being able to link to thread pitches on tapped holes or with not being able to link to number of instances on any hole type. That is why I am starting to play with the built in hole callouts.
My question: Is there a way to insert a SW hole callout to a sectioned view of a hole rather than a top/bottom view of the hole?