Tax issues constantly involve grey areas. You balance your risk of reassessment. I'm not sure I agree with the "profit on the taxes", as the purpose of the quick method is to cushion the loss of the input tax credits. If you don't add the Gst on the expenses, then you really are making a profit on the taxes. If, as CRA says, you remove the GST from the expenses, you are reducing your expenses but adding 2% of the GST as income.
We may not be able to give you an absolutely definitive answer, and overtaxed and I might or might not make the same deductions ourselves in the same situation. I would include the GST in the expenses because then, in my mind anyway, the 2% GST credit more accurately balances the expense debits.
