Has anyone actually built a warm handoff into their SMS workflow or is every service just dumping names into a spreadsheet

The two-hour claim from the Phoenix shop is the one I'd pull on hard before signing anything. Ask them what "work" means. In my experience running payment tracking for a guy who sourced rural parcels through a hybrid SMS and cold-call setup in southern Arizona, "worked" meant a caller left a voicemail and logged it closed. That is not the same as a live conversation and they will not volunteer that distinction unless you make them define it in writing before you pay.

The Pima County timing problem your guy described is real and it compounds in specific ways out here. A lot of the motivated sellers on those landlord lists are older, own free and clear, and are reachable on a pretty narrow window, late morning or around four in the afternoon, because they have routines and they are not glued to their phone. The six-hour warmth window he mentioned is probably shorter on weekends and longer on a Tuesday. What I never saw any service actually measure is whether the response came in during business hours or at 9pm, because that changes the math on who can realistically call back within two hours. Did he tell you what percentage of his responses come in outside of a normal calling window, because that would tell you whether the two-hour SLA is even physically achievable on your list or just a number that sounds good on a proposal?

Your guy is right that the warm window is short. Six hours is probably generous for a text response. Someone who texts back is signaling immediate availability, and if nobody calls within the first hour or two, the emotional moment that made them respond is often gone by the time anyone picks up the phone.

On your actual question: I have not seen published data that compares follow-up speed to contract rate across the same list in a controlled way. If that research exists, I would want to know who funded it and how "contract rate" was defined, because a service measuring leads-to-conversation and an investor measuring conversation-to-signed-contract are counting different things.

What your Phoenix example revealed is genuinely useful even without the numbers. Two-hour response and end-of-day batching are different products. When you evaluate a service, it helps to ask specifically: what triggers the callback, who makes it, what is the maximum time between an SMS response and a live human voice, and how do you document that timeline so you can audit it later. Proposals that cannot answer those questions concretely are probably in the end-of-day camp regardless of what they say.

The thing you may not have fully priced yet: even a two-hour service cannot fix the gap you described on the Grant Road situation. The investor workflow has to match the speed of the lead. If your capacity to respond fluctuates because of other active deals, a faster service charges you for warm leads that still go cold on your end.

Do you currently have any coverage arrangement when you are unavailable, or is everything running through you directly?