Mold specialist/experienced help needed

Ending my contingent period on a home bid. My inspector was able to identify what may appear as mold. The Seller mentioned that is just mildew. We are currently awaiting results from the lab and if its mildew the seller agreed to clean it but if it is mold its a stand off between us(buyer) and the seller on who will pay for the fix. What do you all think this may be? Thanks