Why db hints doesn't work?

Hi, experts.
Why hints doesn’t work? It’s just ignored.
i’ve created a simple program and try to use ‘ %_hints db2 ‘&max_in_blocking_factor 100&’,
but it;s just ignored.

data : lt_tab type table of mara,
lt_Tab2 type SORTED TABLE OF makt WITH UNIQUE key matnr spras.

select * from mara into CORRESPONDING FIELDS OF TABLE lt_tab.

select * from makt APPENDING CORRESPONDING FIELDS OF TABLE lt_tab2
FOR ALL ENTRIES IN lt_tab
where matnr = lt_tab-matnr
and spras = ‘E’
%_hints db2 ‘&max_in_blocking_factor 100&’.

As i understood ‘FOR ALL ENTRIES’ takes for 30 records and when i try to set more it’s just ignored.