Has anyone ever seen where a weighted average element works for one employee but not another?

We have an element set up in EBS.  The element is setup to be included in weighted average calculation.  The element works when paying one employee but it doesn't work for another employee.  The exact same elements are entered for each employee.  The employees do have different rates.  However, one is full-time and one is part-time.  But I changed the part-time employee to a full time employee and the calculation still did not work.