More than likely the inventory valuation method may have changed midway through receiving these parts, and therefore, the cost is taken from a different place (estimated cost versus PO price).

Alternatively, the cost part rollup may not have been executed, but this will depend on how the part cost is made up - do you have specific details of a part that you can review the above mentioned settings?

Nick - I found a particular part that is a good test.  I have receipts for the part before and after the date where the RNYI sourcing appears to change.  

Inventory Valuation Method is currently “Standard Cost”

Inventory Value/Unit Cost is currently $0.50

Part Cost/Total Cost is currently $0.00 for all cost sets

There are 7 received not yet invoiced receipts on the report

The RNYI report uses the  $0.50 for the first receipts, after that it uses the various buy unit prices on the POs.

In the Inventory Transaction History/Accounting tab, there are PRICEDIFF- (Price Difference - Lower Price) and PRICEDIFF+ (Price Difference - Higher Price) for each receipt where the PO buy unit price differs from the Inventory Value/Unit Cost.   Posting Types for those are M10 (Receipt with Purchase Order) and M20 (Price diff Purch, Loweruor Higher] Price).

For the record, I was able to get over my immediate need by incorporating the above accounting transactions into my report code - didn’t mention it, but that’s what I was trying to do, write a report.

So all that is left is my curiosity to understand why the change happened.