In the preferences I see many options for choosing the calculation options. To get to the correct and accurate predictions which option shall I choose "Default Calculation Options" or "Calculation Options Recommended by the Author"? There is a time gap of around 6 months e.g. If I choose the "Calculation Options Recommended by the Author" all the Dasas starting time changes to 6 months earlier.. Can anyone tell me what is the right calculation option?