This read-only TimeTicks value, relative to sysUpTime, records when the self-tests listed in wvLastSelfTestTable were last actually executed. An admin checks this timestamp to confirm self-test results being reviewed are recent and relevant, rather than leftover from a much earlier maintenance session. For example, if wvLastSelfTestStartTime corresponds to a time three months before sysUpTime's current value, the admin knows no self-test has been run since then and should schedule a fresh one before trusting the terminal's health status.