Why are you interested? So that you can add more information to your "How I can pretend to sound like an airline pilot" folder? I am going to keep my information about how to calculate a ToD in my SAPB folder. The information you have provided to calculate the ToD is just stupid and has some very unrealistic assumptions. I will leave you to discuss with other pilots within your "airline" when next you are in your "crewroom" what the unrealistic assumptions are.