A computing system identifies multiple matching points between (i) query fingerprints representing a media stream being received by a client and (ii) reference fingerprints, each identified matching point defining a respective match between a query fingerprint timestamped with client time defined according to a clock of the client and a reference fingerprint timestamped with true time defined according to a timeline within a known media stream. Further, the computing system performs linear regression based on the timestamps of the matching points, to establish a mapping between true time and client time. The computing system then uses the mapping to determine a client-time point at which the client should perform a content revision or other action with respect to the media stream being received by the client. And the computing system causes the client to perform the content revision or other action at the determined client-time point.