I can enter different dates (Earliest, Target, Latest Date) for a one-time goals when calculating the Balance Sheet. What date does it use to calculate the cash flow?

The use of different dates (Earliest, Target, Latest Date) comes into play only for one time (lump sum) goals. All the dates are used to calculate the cash flow. The reason for the different dates is to calculate the impact of time and effort on one time goals. Using all three dates, a continuous solution is created. An incremental amount will appear for the lowest goal priority level on the Household Balance Sheet if an earliest date is entered that is different than the target date. To avoid having an incremental amount for the lowest goal priority level, set the earliest date equal to the target date.