Thank you Olly, that seems to have done it. :)
In case someone else needs the same type of operation, I took what Olly gave me and did the following:
Label [unique] 4 – up to 5 – Delivery Charges 2.00
Label [unique] 5 – up to 6 – Delivery Charges 3.00
Label [unique] 6 – up to 7 – Delivery Charges 4.00
Label [unique] 7 – up to 8 – Delivery Charges 5.00
Label [unique] 8 – up to 9 – Delivery Charges 6.00
Label [unique] 9 – up to 10 – Delivery Charges 7.00