Percona 5.6 - Process List - Difference between TIME and TIME_MS

Percona Server 5.6 [INDENT]
[LIST]
[]PROCESSLIST table:
[LIST]
[
]added column TIME_MS
[/LIST]
[/LIST]
https://www.percona.com/doc/percona-server/5.6/diagnostics/process_list.html

[/INDENT] You would expact TIME = round(TIME_MS / 1000) but this isn’t always true, why?

You can see examples of this on, https://bugs.launchpad.net/percona-server/+bug/1402954
TIME: 8
TIME_MS: 161
or
TIME: 106
TIME_MS: 2175