Although internal calculations are carried out using double precision numbers, results are only stored as single precision numbers (in order to reduce storage requirements). As a result, result values can only be relied upon to a maximum of 7 significant figures. For date outputs (e.g., outputs of the Milestone element), dates displayed in and around 2000 are only accurate to approximately 2 minutes.
This also means that when results are viewed in tables or charts, the range of values that can be displayed is between -1.2E-38 and 3.4E38.