PL/SQL :: How To Free Temporary LOB Returned By A Function

I have a business need to have a db function that would construct and return a (temporary) CLOB value.

here is its sample code:

create or replace package PKG_TEST_CLOB
as
function FN_TEST_TEMP_CLOB
return clob;

[code]....

when this function is invoked from a SQL Statement...

***
select PKG_TEST_CLOB.FN_TEST_TEMP_CLOB from dual;
***

... the NOCACHE_LOBS counter in V$TEMPORARY_LOBS for my session is incremented by 1

when this function is invoked via a PL/SQL block...

***
declare
l_clob clob;
begin
select PKG_TEST_CLOB.FN_TEST_TEMP_CLOB into l_clob from dual;
end;
/
declare

[code]....

... the counter doesn't budge

In real life, this function will be used by a Reporting Tool (cognos) via SQL. I tested it, and it seems that it is allocating a new temp lob segment with every invocation.