The wristwatch times listed were converted to decimals to reflect how a Hobbs would display the times (in my experience they were all oil pressure activated and ran very accurately at .1Hobbs=6mins)
Actual IFR and other entries I have always logged as good 'guesses'...I can't go hit a timer every time I enter a cloud.
Generally there is enough going on that I end up forgetting to start/stop a timer simultaniously with engine start/shutdown, which is probably why they have Hobbs timers to begin with.