Thank you for your response. 

Since Political Contributions 41000 are listed in the section which is "Refund or Balance Owing" why wouldn't such a contribution, which would be a credit, offsetting any taxes added in that section e.g  at 42800, and then net out at 43500?

It defies logic that anyone with a refund should be unable to receive such a credit.  Since a huge number of taxpayers do claim refunds this will thwart fundraising efforts by political parties.