The PO will update the recent cost in IC if the recent cost is blank or $0.00, say in the case of a new item created. Otherwise the cost gets updated as reported above.
The reasoning behind updating the recent cost when the PO is created (if recent cost is zero) is so that you could ship, invoice, and do the EOD processing in OE before the item is actually receipted in PO's, which in previous releases did not update the recent cost, which resulted in a zero cost and also required the PO End of Day to be run before OE End of Day. This now gives you flexibility to run your EOD's in either sequence.
Brian