I made the test and it did not give to 160KB and yes 160 MB. I have the habit esteem the size of the short while bigger table of the one than its initial size, this prevents spalling and for the NEXT I normally place I eat 10% you the total size of the table.

SQL> Create table teste
2 (COMPANYID number,
3 OBJECTTYPEID number,
4 OBJECTID number,
5 PROPERTYID number,
6 SEQUENCE number,
7 VALUEPROPERTY varchar2(50))
8 ;

Table created.

SQL> select table_name tabela, (sum (data_length) / 1048576) * 1000000 "Length MB"
2 from dba_tab_columns
3 where owner = 'MARCIO'
4 group by table_name
5 ;

TABELA Length MB
------------------------------ ----------
PLAN_TABLE 1566.8869
TESTE 152.587891