Daily duration time options
When I ended work at 1.00 AM and turned off computer, and then turned on computer again at 20:00 - Daily Duration chart tells me, that I've worked 20 hours. It should count only time when computer is turned on.
You can use Settings, General, Time shift to shift working day. Set to for example 4, that would mean that days are counted from 4am to 4am and this should then work correctly.