Is Bathing and Grooming Rate something that would be in addition to my Drop-In Visit costs?

I enjoy bathing and grooming dogs so I am wanting to go ahead and set a rate for bathing and grooming a dog during drop-in visits. My issue is that I have no clue if the Bathing and Grooming Rate is something that would be in addition to my Drop-In Visit costs or if that would be the total for the Drop-In Visit and the bath.

ex. If I had a Drop-In Visit rate of $10 a visit with a Bathing and Grooming Rate of $15, would the final cost for one visit with a bath and grooming be $15 or $25?