This question is relevant to me as well - I need to show GST as an additional fee so that the client is shown the 'real total' before being sent to the PayPal site.
Even there (in PayPal) the tax is not added until AFTER the client has entered all of their details & payment information and is ready to hit Pay Now.
For someone like me who knows nothing about coding, this extension has had a bit of a learning curve, but nothing too difficult for sure and it is worthy of mainstream promotion. I only get frustrated when I come to find answers on a forum, find a topic that is exactly what I need but there is no follow up or response included.
If there is in fact a way to add an additional fee(s) this would also be useful for upselling reading material or other add ons that a person could purchase in preparation for a course/workshop.
My ultimate question is how to add tax in as an additional fee (5%)
Any cost added by a custom field is what shows as an "Additional Fee". This would be anything added by a dropdown, checkbox or radio button fee field. You can change the words "Additional Fees" in the language file. You could of course add your tax in this way. It just would not be labeled as a tax. We will look to add a specific tax feature in a soon release.