If there is no actual inventory count for WIP inventory, only a dollar amount, then what is the WIP Evaluation report as found in the Inventory Control reports listing?
The WIP Evaluation Report  is a calculated value of inventory that was kitted. It may or may not equal the accounting value of WIP, as the accounting value can be adjusted by transactions outside inventory, such as journal entries. But the WIP report will be a very close approximation of the WIP value. It is determined by the following sequence:

First, only open work orders are considered. Closed or Cancelled work orders are not included. Then the balance of assemblies due for each work order is determined. For each work order included, the original quantity of each part kitted for the work order is determined based on the kit pull, and extended by the balance of the work order, and by the standard cost of those parts. Then kit shortages are checked. All shortages for the work order are then subtracted from the total value of the work order. This information is then displayed within this report. 

This information continues to be reported until the balance of a work order is zero and the kit is closed. At that point, all WIP value associated with the work order is returned to zero.