Receipting items from a PO not working?

Hi
We are having issues with receipting inventory from a Purchase Order.
Please see the example shown in sequential attached files.
I start with a Purchase Order (PO) for 2 items of inventory.
When I receipt the inventory on one of the lines of the PO the line item totals - that previously contained total amounts (QTY x Unit Price) - now show $0?
There is no discount applied and no other input other than to receipt the 5 units of stock from the first line of the PO.
Steps taken are:
1 - Enter PO into MYOB
2 - Go back into PO and click "Receipt Items", and receipt 5 units of inventory from the first line
3 - Go back into the PO after receipting the inventory to find that the Total Column no longer works for items not receipted?

Please can you let us know if we should receipt items (not yet Invoiced) in some other way?
Many thanks!