Is this extension compatible with 3rd party one step checkout extensions?

The extension uses standard Magento features to add its own total.

If the checkout extension was made correctly, there shouldn't be any problem with the fee total.
However, some extensions don't refresh the block with totals after selecting or changing the payment method — in this case the fee won't be visible for the customer during checkout, but it will be added to the grand total (the customer will see it in the email and order history) or after refreshing the whole page.

Last modify date: Wednesday, October 12, 2016