You should expose to the outside world only what the outside world really needs. It is often best to add functionality for consumers of the class when it is needed, rather than at first. These days the wisdom is to avoid pre-engineering. (see YAGNI)
It can certainly be acceptable to have public methods that are also used by other functionality within the class. However, this should be considered a minor bad smell. It might be an indication that your class is trying to do too many things.
My guess is to leave your classes as they are. Then, when these other, smaller methods are needed by the outside world, consider if you should separate your classes. If the purpose of each of these classes to to yield one report, then you should not expose these methods from this object. Instead, put "smaller" methods into a common helper class. That way they are available to the outside world without fundamentally changing the nature of your existing report classes. In short:
Don't just do it because you think it might be helpful later. If/When the additional functionality is needed, reconsider your overall design to accommodate the new requirements.
