Swamp76,
If you've been to Port Harcourt you'd know that the engineers are not in the hangar from 0600 to 2200 (which by the way is 16 hours). They do a spell on earlies from 0600 to 1400 and a spell on lates from 1300 to around 2100. On the changeover day from earlies to lates they get a 24 hour break (which I totally agree does not equate to a day off.
The pilots on night standby all have a day off after finishing their night standby.