Database.ExecuteSqlCommand returns incorrect rowcount

I'm using context.Database.ExecuteSql to update a table. The update with where clause is executed correctly and the record is updated. However the method returns 2 for rowcount instead of 1. When I execute the update statement in SSMS, the result rowcount returned is 1. Can someone provide insight on this?

            string query =
            string.Format("update {0} set Description = '{1}', Code = '{2}', LastUpdatedBy = '{3}', LastUpdatedDate = '{4}' where ID = {5};",
                tableName,
                description,
                code,
                lastUpdatedBy,
                lastUpdatedDate,
                ID);

        int rowCount = 0;
        string message = string.Empty;

        using (DBContext context = new DBContext())
        {
            rowCount = context.Database.ExecuteSqlCommand(TransactionalBehavior.EnsureTransaction, query);
        }

        return rowCount == 0 ?  //this return 2 instead of 1.
            new SaveResult(SaveResult.MessageType.Error, string.Format("There was an error updating a record in the {0} table.", tableName), "Index") :
            new SaveResult(SaveResult.MessageType.Success, string.Format("The update of {0} was successful.", tableName), "Index");

This returns rowcount = 1 in SSMS:

update zAddressTypes 
set Description = 'Current', Code = '101122', LastUpdatedBy = 'user', LastUpdatedDate = '10/20/2014 12:17:26 PM' 
where ID = 1; 

DECLARE @RowCount INTEGER = @@ROWCOUNT; 
select @RowCount;