Magento 1 EE: Onestep checkout Grand Total Issue

Question

I'm facing the weird issue,

On the Checkout page, on load Grand Total is displaying correctly.

but when I choose the shipping method it add the tax value to the Grand Total (even when the backend tax setting; Include Tax In Grand Total-No)

I also checked this with the base theme and still, the issue is same.

Please suggest.

Answer 1

The issue and solution depends on what module you are using. Every providers One Step Checkout module is different code. Please contact module providers support and they are the ones who will be able to and should help you out.