Hello, @topherfarrel.thank you for getting in touch with your inquiry. I'm pleased to provide some insights in managing sales.

Prior to the update of QuickBooks Desktop, everything was running smoothly. You've noticed that the shipping cost alters when switching classes, which is unexpected. Altering class lists in QuickBooks Desktop is not supposed to impact the shipping charges. If you continue to encounter difficulties with data transactions, here is a guide to help you address and resolve possible issues within QuickBooks Desktop.

For error messages or unusual activity in QuickBooks Desktop, use the Rebuild and Verify Utility. This is the first step in resolving data issues:

Run Rebuild Utility:

1. Open the QuickBooks Utilities menu and click Rebuild Data.
2. Click OK if asked to back up your company file.
   Note: If you see "QuickBooks is not responding," don't worry. As long as your mouse moves, Rebuild is still working. Just wait. 
3. When you get the message that Rebuild is done, click OK and go to the next step.

Run the Verify Utility:
 

1. In the QuickBooks File menu, go to Utilities and click Verify Data.
2. Click OK if you see "QuickBooks detected no problem with your data" and continue using your company file.
3. If Verify finds a problem with your date, you'll see see options to Rebuild Now or View Errors.
4. Click Rebuild Now.

If this doesn't fix the issue, please refer to this article and be guided properly: Fix company file and network issues with QuickBooks File Doctor.

Once become all handy, you can access to this article: Create an invoice in QuickBooks Desktop.

Our dedicated team is available 24/7 to assist you with any other concerns you may have in managing your sales. Just hit Reply, and we will assist you right away.