(a) A penalty of 10 percent of the unpaid amount of taxes shall accrue immediately on default of payment of taxes after the 60 days.
(b) An attorney's fee of 10 percent of the unpaid amount of the taxes is due and payable immediately on institution of suit for collection and foreclosure.
(c) The penalty and attorney's fee shall be recovered in the suit and shall constitute an addition to the taxes and shall be secured by the tax lien.