In certain scenarios you may wish to have a maximum or minimum shipping charge for a certain carrier. For example, you might want to charge the rate UPS returns for UPS small package services but charge at least $25 or you might want to charge whatever YRC returns for LTL freight but never more than $1000. You can set this up using the Minimum and Maximum charge fields on your carrier.
These settings will override any Carrier Rules, Handling Fees, Per-Box Fees surcharges you may have set up. Because of this, most merchants can leave these fields set to their default values.
On your carrier under the Advanced panel you’ll find the Minimum Shipping Fee and Maximum Shipping Fee fields. The value you enter here will override the rate returned by the carrier if under or over the values set here, respectively.
If these fields are set to 0.00 they will be ignored.