PL/SQL :: Create Script That Makes Added Year Worth Of Partitions Less Manual?

mucking on an Oracle 11.2 database, simple range partitioning issue. Seems using a "complex" formula inside the AT clause annoys it? Or am I doing something wrong?

I create the table with RANGE partition just fine:

CREATE TABLE my_part_tab
   ( id        number,
     sdate     date
     )
PARTITION BY RANGE ( sdate )
      (  PARTITION P2013Q1 VALUES LESS THAN ( TO_DATE('01-jan-2013','dd-mon-yyyy') ),
         PARTITION P2013Q2 VALUES LESS THAN ( TO_DATE('01-jul-2013','dd-mon-yyyy') ),
         PARTITION P2013Q3 VALUES LESS THAN ( TO_DATE('01-oct-2013','dd-mon-yyyy') ),
       
[code]...

Table created.(and yes, I'm aware of INTERVAL option that'll do this next part "automagically", however, INTERVAL and REFERENCE partitioning are incompatible, and the child table is using REFERENCE partition). to make things easier on DBA for future, I'm trying to create a script that makes added a year's worth of partitions less manual.So far, I have the following working:

ACCEPT lYear PROMPT "Add Paritions for which calendar year?"
ALTER TABLE my_part_tab SPLIT PARTITION PMAX
   AT ( TO_DATE('01-apr-&lYear','dd-mon-yyyy') ) INTO ( PARTITION P&lYear.Q1,PARTITION PMAX );
ALTER TABLE my_part_tab SPLIT PARTITION PMAX
   AT ( TO_DATE('01-jul-&lYear','dd-mon-yyyy') ) INTO ( PARTITION P&lYear.Q2,PARTITION PMAX );

[code]...

But no luck ...Same issue with other variations:

ALTER TABLE my_part_tab SPLIT PARTITION PMAX
   AT ( (ADD_MONTHS(TO_DATE('01-jan-&lYear','dd-mon-yyyy'),12)) ) INTO ( PARTITION P&lYear.Q4,PARTITION PMAX );
ALTER TABLE my_part_tab SPLIT PARTITION PMAX
   AT ( (TO_DATE('01-jan-'||TO_CHAR(TO_NUMBER('&lYear')+1,'fm9999'),'dd-mon-yyyy')) ) INTO ( PARTITION P&lYear.Q4,PARTITION PMAX );