An error occurs when I use "Flat Rate Shipping" for domestic orders when I use the "Additional Item Cost" box. Here is the scenario:
First Domestic Service: US Postal Service Priorty Mail
Cost: $9.98
Additional Item Cost $8.98
Error Message in red: Additional Shipping Cost Invalid
This only happens when my additional shipping is $8.98. If I lower the cost to $7.98, there would be no error.
How can I fix this?
Thanks!
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