Pricing a market entry study when the client wants a go/no-go answer

A regional operator asked me to scope a study on whether they should enter a secondary metro with a 200-unit build-to-rent pipeline. They want a recommendation, not a data dump. My draft scope has rent comps, absorption from the last three delivery cycles, permit pipeline, and interviews with two local brokers and a municipal planner. I priced it at 28k, roughly 90 hours at 300 plus data costs around 2.5k for the CoStar pull and a demographic subscription.

The part I can't settle is the liability shape of a go/no-go. If I hand them a recommendation and they commit 40m and absorption comes in half of what the permit pipeline implied, I own the memo. If I hand them a range and let them decide, they'll say they paid for judgment and got a spreadsheet.

How are people structuring the deliverable so the recommendation is real but the conditions under which it holds are on the page? I've seen engagement letters that list explicit assumptions with a clause saying the conclusion is void if any of them moves more than a stated threshold. That feels like it works until the client's lender reads it. Also curious whether anyone prices the go/no-go higher than the same work delivered as a findings memo, and by how much.