Liveupdate policy for clients have a schedule to do a liveupdate from the manager
Having the communication settings determine when a liveupdate from the manager can result in updates coming when a system is busy. Suggested that the communications settings be set for updating policies and sending logs from the clients and have a scheduled in the liveupdate policy for the clients to get the updates similar to the ability for the clients to go out to the internet for updates.
This way you could schedule updates according to when the clients are not busy to get updates rather than having the manager sending updates when they are available to the clients.
If this is done, another command would be needed when you right click on a client or group to Update Definitions for the clients to force an update to the clients from the manager in times of a threat outbreak.