Hi John,
Below are few suggestions for your scenario.
Different discounts models depending on order value
--> this can be accomplished by using scales for your discount condition in the contract master.
Minimum order values
--> this can be controlled thru info records for vendor material combination. As MOQ is to be taken care during contract releases, info records can be used to accomplish the same.
Different invoicing terms based on order value
--> I couldn't figure out a standard way for this.
Extra delivery costs for urgent deliveries
--> as this will be known only during contract release order, can use a special freight condition to capture this in the release PO.
Thanks,
Kalai.