The pause your contact took is the tell. He experienced the outcome, not the process that produced it.
The assumption doing the most work in his account is that four showings by Friday was the result of MLS placement. It probably was not. In a supply-constrained market like Spokane's north side multifamily segment, the listing agent's pricing decision is where most of the leverage sits, and pricing is almost entirely invisible to the seller after the fact. If she talked him down $18k from his first instinct and landed at a number that put the property inside the search thresholds buyers and their agents were actually using, that single call likely generated the showing velocity he attributed to the MLS.
The other thing he cannot see: how she managed the four offers to produce a full-price result rather than a bidding war that collapses, or a low anchor that sets the tone wrong. Offer management and seller coaching through that window are not visible in the outcome either, only in the absence of problems.
The risk he did not mention, and that you should think about for your own situation, is that a smooth close makes it easy to underprice the agent's contribution when you negotiate commission next time. If pricing and offer strategy are where the value is, then the question worth asking before signing a listing agreement is not "what is your commission" but "walk me through how you arrived at your price recommendation and what you do when the first offer comes in below asking."
Your duplex is under contract off-market, which means you already bypassed the listing process. When you do eventually use a listing agent, the guide content on the strategy page is worth reading for what the post-2024 commission framework actually changed on the seller's side versus the buyer's side, because the two are not symmetric.
What did the agent recommend for list price on the fourplex relative to recent comparable sales in that submarket?