There are certainly some things you could calculate for yourself. But why? Just for an example, suppose you want to know what e-time you are owed for a duty period. This involves translating the departure and arrival back to home-base-time and then following complicated rules on which of the hours should be counted at 2:3 and which should be counted at 1:2 and then adding it all up. Who has the time?
Notice especially the yellow highlighted area below. There we divide up the hours and give a footnote explanation for how the calculation was done.