cmLoopHistTimeElapsed is a read-only TimeTicks value recording how long a completed loopback test actually ran, as preserved in the history table. An administrator compares this to cmLoopHistDuration to see whether a historical test ran to its full configured length or was cut short. For example, a short cmLoopHistTimeElapsed relative to a much longer cmLoopHistDuration would tell the operator that test ended early, perhaps due to the operatorStopped or noCPEresponse termination reasons.