The scheduled tasks is a way for a unit to perform song time consuming activities asynchronously from CRON. Currently each unit can only register it's own scheduled tasks. This doesn't sound like a restriction, but in world where each module can extend units from modules it's quite a restriction.
Allow specifying own/another unit prefix during scheduled task registration. Example:
It's also easy to implement, by changing 1 line in
kUnitConfigReader::parseScheduledTasks method (5.2.x and below). Code was moved in 5.3.x release.