What does your Broker say?
They are most familiar with your situation.
When I am working with a Seller, I determine what is best for the client based on their current situation and go from there.
Rebekah Owen, MBA
While it may seem none of their business how much you paid, the fact that they were completed by a qualified professional is important for the Residential Service Contract. You should be able to get a statement from any professional completing work that he did the work and stands behind it (for a specified short period), if you really want to keep your costs hidden.
If the professional won't do that, then you have to ask yourself the question of whether their repairs are truly of a quality you would want done on a house you were buying.
One thing to keep in mind is each transaction is different you should discuss this in detail with your listing agent. If, you the seller are not represented by an agent you should contact a real estate attorney in your area for advice.
That way there is a record the repairs were done and what was done. In my experience buyers who are asking for repairs are going to come back and check them before closing as well.
The more disclosure and transparency the better in most cases. If you somehow don't disclose the amounts I might think you were trying to hide something....that's just my take.
Your listing agent can review terms and conditions of sales contract with you