Cause: System shows Invalid Rate! (Rate can be less than PO Rate for this item, but cannot be more.) on despatch confirm, when the customer is channel partner and hence on the dispatch confirmation , the system is generating the Purchase receipt as per the dispatch details.
But in open Purchase order, the rate is not matching as per the dispatch.
Remedies:
As per channel partner flow, we can make a standing Purchase order in the supplier site for so when ever the ware house will sale something to the Channel partner customer then it will create auto Purchase receipt on posting of invoice and simlarly
when the Purchase return is made at Supplier site automatic Sales return is made at the customer site.
User needs to ensure while sale to customer the rate of the item should be equal to Purchase order rate.