Cost resources are not settled

Peter --

If you assign an Expense Cost to a task and it is the ONLY resource assigned, and then you click the 100% Complete button, Microsoft Project will automatically set the Actual Cost value to the Cost value and the Remaining Cost value will be set to 0. If you assign one or more Work resources AND an Expense Cost resource to a task, and then you click the 100% Complete button, Microsoft Project will automatically set the Actual Cost value to the Cost value and the Remaining Cost value will be set to 0, but ONLY FOR THE WORK RESOURCES, and it will not enter any Actual Cost value for the Expense Cost resource. This is not a bug. It is simply how the software works. My personal recommendation is to always manually enter the Actual Cost values for your Expense Cost resources using the Task Usage view with the Cost table applied. Hope this helps.