Auto Calculate Shipping by Percentage %

Hi! It would be nice if on Quotes, Invoices, etc… there was a way to calculate a Total Shipping fee based on a specified percentage the same way taxes are automatically calculated. Many of us charge a set fee based on a % to cover freight, shipping and white glove delivery and it would be great if this could be automatically calculated for us and specified in its own line somewhere on these documents. Right now, we must do this manually and add it as a line item on the invoice. I would love to see another field under Taxes that says “Shipping” that populates this cost. I hope this makes sense. Thanks for considering this request. Destini