Make Summoning Rock more available

Suggestion Title: Hermit need Summoning Rock to use Shadow Partner. Is it possible to make Summoning Rock available in NPC shops? Description of Suggestion: Hermit need a vast amount of Summoning Rock if one want to use Shadow Partner frequently. Currently I don't know an easy way to vastly acquire it. It would be very helpful if we can just buy it in NPC shops. It would affect Hermit a lot. (If there is already a way to acquire, pls inform me.) Why Do You Think This Is Needed? Improve game experience. Possible Downsides or Obstacles: Perhaps it might affect the balance between jobs? Might make Hermit too strong? Additional Notes/Comments: N/A