some question about Incrementally Updated Backups

 hi, i found that Incrementally Updated Backups is very good ,but i have some question about it

from Oracle® Database Backup and Recovery Basics 10g Release 2 (10.2) and other place 

the example of  Incrementally Updated Backups  always is 

RUN {
   RECOVER COPY OF DATABASE WITH TAG 'incr_update';
   BACKUP INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG 'incr_update'
       DATABASE;
   }

why recover is first and then backup a level 1 ,then when we need to recover database ,we need to apply a level 1 backup and some archivelog 

if we can change the order ,like

RUN {

  BACKUP INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG 'incr_update'  DATABASE;