When Salaries and Service are calculated, ProAdmin tries to assemble all the dates it thinks you will need (including any dates associated with any array fields used in the expression). These dates are represented by the operator #DATE. So, when a temporary variable is assigned an array field, the values in the array field are associated with specific dates in #DATE, and if you are doing an Estimate Calculation, the values will be projected. The reported values in the last measurement period are used to derive a full measurement period value, and then that value is used as the projected value and allocated to each future measurement period. (In Hours and Multiplier transformation expressions, they are allocated using calendar days; for Salaries, they are allocated using the Salary Definition's allocation assumptions.)