Currently, under the Departure and Arrival columns in my logbook I am entering the take off time and the landing time, then in the Total Time Of Flight column I am entering the time of flight plus 0.2 for taxi.
Surely if you're doing that then the time in the total column doesn't equal the arrival minus the departure time?
This sounds like an absolute mess.
If I were you I'd start again, the departure time is when you start moving on the ground with the intention of flight, not your take off time, and the arrival is when you park up and shut down, not when you land.
This is actually written in the instructions in the front of every logbook I have ever seen. I really don't see why people struggle.