Whenever any accounts for delinquent property taxes owed to the city
are given to its tax attorney for collection, on or after July 1 of
the year they become delinquent, the city shall be entitled to, and
shall collect, an additional penalty of fifteen percent (15%) of the
delinquent taxes and penalty (including any interest owed) due on
each delinquent property at the time of collection, either before
or after suit and/or foreclosure sale, as provided by section 33.07
of the Texas Property Tax Code.