CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;
CONFIGURE RETENTION POLICY TO REDUNDANCY 5;
The recovery window is used to make sure that there are always sufficient backups to recover the database to any point in time with the last 'X' days. Any backups that fall outside this time period can be deleted. The redundancy option simply states that any backups in excess of the latest 'X' are no longer needed.
In other words, setting the RMAN retention policy to a recovery window explicitly guarantees PITR to any time within the recovery window. It isn't clear from this description whether PITR is guaranteed using the alternative redundancy configuration — does RMAN retain all archivelog backups necessary for PITR to any point since the earliest retained backup?