If you've enabled the Walmart 2 Day Fast Tag, then you must set you must your standard processing schedule to Eastern Standard Time. If this is not done, then Deliverr will auto-upgrade orders received, which you will be charged for.
To correctly set the your standard processing schedule, please follow the below four steps in Walmart Seller Central.
Step 1 - Log into Walmart.com seller central, and click settings.
Step 2 - Click shipping.
Step 3 - Under 'What timezone do you primarily ship from?' select Eastern Standard Time.
Step 4 - Scroll to the the bottom of the page, and click Save.