why not tax the resources?, page-17

Davo am i wrong about the gst being exempt for export companies? And well if the simple way im looking at the tax and we all know we can complex anyones tax is correct?If say your profit doubled for same costs and output you would be subject to a ten percent rise .If you had same output and cost and price was within your normal operating levels then you would pay 30% If it goes below your normal operating range then your tax would also go lower than 30% Dont worry about the more complex parts of depreacations etc etc This is how it works or not?Much appreaciated.