Shipping charges more than the customer pays at checkout

I’m having an issue where the shipping charge a customer is quoted at checkout is often less than what I actually end up paying when I create the label. My average order to fulfillment time is under 5 hours. I use UPS(85%) and USPS (15%) of the time.

Is there a way to “fix” this so I’m don’t have to constantly cover the difference between what the customer is charged for shipping and what I actually pay for the label when I ship it?