According to documentation System policy: LiveUpdate scheduling settings randomization is available only for Daily or Weekly schedule settings.
Hours settings approach this topic different way.
SEP clients configured with Liveupdate policy.
When the schedule is set to "hours", the configurable randomization feature does not function as expected. However, in this scenario, another inherent mechanism ensures
that the download process remains essentially randomized. This occurs because the timer for LiveUpdate starts from the last time the client ran the update.
Given that client systems boot, restart, or have their services restarted at different times, LiveUpdate will effectively run at different times for each system.
This inherent variability ensures that the update process is staggered across network.
You can verify if randomization from policy is enable via registry: