You are in the wrong forum, this was started for the free plugin.
However if you open and read the PDF docs at the paragraph 'Subscriptions and recurring payments' you find the answer to your question in the following explanations:
Don't use taxes or shipping cost (reserved to physical products) when you activate subscriptions.
Paypal will ignore both taxation and shipping amounts when dealing with subscriptions and recurrent
payments and using them would be confusing for customers.
Paypal doesn't support subscriptions with added values for taxes, fees, shipping costs, etc thus if
you have extra costs for taxes the best solution is including them in the product price itself.