A 92 percent delivered rate doesn't clear you, because delivery receipts and carrier-level filtering aren't measuring the same event. Messages can be accepted by the carrier and then dropped or held before the handset, and some aggregators report those as delivered. Pull raw error codes by carrier and by sending number rather than the blended dashboard figure. If one carrier's delivered rate is 97 and another is 71, that's filtering. If all carriers look identical and your reply rate still halved, it's the list.
Four passes over the same absentee file in three counties is a lot of passes. Split the next send: one cohort of numbers you've messaged four times, one cohort never touched, same template, same day, same time. If the fresh cohort replies at 4 percent, saturation is real and your vendor is right for the wrong reason. If the fresh cohort also comes in near 1.2, the problem is upstream of the list.
60 numbers pushing 15,000 a day is around 250 per number, which is the volume profile carriers associate with snowshoeing, and spreading traffic thin across many numbers to dodge filters violates carrier policy on most networks. Registration under 10DLC does not immunize you from content and traffic-pattern filtering, and your provider can deregister a campaign with very little notice. Confirm your current campaign standing and throughput limits with your provider in writing.
The thing that costs more than the response rate is opt-out hygiene across 60 numbers. If suppression is per number rather than per contact, someone who opted out of number 12 gets messaged again from number 40, and consent rules for texting differ by state on top of the federal layer. That's an exposure question for a telecom compliance attorney, not a dashboard question.
