We have a number of settings to help you control the buying process, related to specifically the receipting of deliveries - GRN's.
Invoice Alert - When creating an invoice against an order, if enabled, you can warn the invoice creator that the order hasn't been fully receipted. You can even prevent the order from being raised.
This is enabled and the setting chosen in Business > Settings > Validations
Prevent additional GRN's - You can prevent an order being receipted further, once it balances as being fully delivered. This means if you ordered 10 widgets and someone has receipted the delivery of 10 widgets, with this setting on, no additional receipting can be done.
Again this is under the Validation tab of the Business Settings
Adjusting the Order to the GRN - We think of this setting as our fresh produce setting. You ordered 25 chicken fillets and the butcher has delivered 18. You won't get 7 on back order. This is all the butcher had for the day. With this setting on, you can adjust the purchase order to reflect the delivery. The GRN is done in the usual way but a conditional prompt will appear if the setting is enabled:
The setting, under Validations, enables you to offer this for all suppliers or suppliers of a certain type.