Purchasing - Payables validation issue

dear,

under the purchasing responsbility we have put the parameter 'over receipt tolerance' equal to 50%; the user is creating a purchase order of 50 items for 10,000$ for instance... while receiving, the supplier is sending

him 60 items for 10,000 instead of 50 items 10 items more than what is asked on PO;

since the tolerance parameter is 50% the user is able to receive and under the accounts payable able create invoice and match the PO however the user when he tries to Validate the system is not letting him to validate?

can anyone help me with this issue? what shall be done?

10x