Is it expected that the Symantec Management Agent would show as running "very high" power usage in Task Manager > Processes?
Release : ITMS 8x
This functionality was added in Windows 10 October 2018 Update Features (Version 1809). This has been reported to Broadcom Product Management for a response as to if this is expected behavior.
Per the following 3rd party article we confirm:
There are a couple of new columns in Task Manager including “Power usage” and “Power usage trend” columns under the Processes tab. This allows you to view the power usage on a per-app basis. This will come in handy when trying to get the most power from your battery each day.
https://www.groovypost.com/howto/monitor-app-power-usage-in-windows-10-task-manager/