Generally agree with the other replies on this thread - my understanding of the ethics code for CPAs is that they cannot charge a contingent fee for professional services if they’re also offering audit/review/compilation services for that client or if the services include reviewing prospective financial information (forecasts). Some firms may interpret these rules as not applying to QoE work but that being said, you do not want to incentivize someone to close a deal if there are really red flags that should be telling you to walk away from the deal. If your goal is to keep costs down, some ways you may try to do that is to limit the scope, ask the seller or your lender to share in the fees, or see if the provider is willing to discount or defer fees until a deal is closed.

If you want to keep costs down in case of a dead deal, look for a firm that will discount subsequent QoE in case a deal goes south.

Not exactly what you're looking for, but can at least take the sting away. Check out: redacted