Change of oraInventory Locations in 10g and 11g

It appears the default or peferred location for oraInventory directory has been changed in Oracle 11g (R1 and R2) versions from that of the 10gR2.
The "Choosing Mount Points" sections in the appendix (B on 10g, C on 11g) is refered it will contain

Directory                            Path
Oracle base($ORACLE_BASE)            /u01/app/oracle
Oracle Inventory                     $ORACLE_BASE/oraInventory
Oracle home                          $ORACLE_BASE/product/(10.2/11.1)11.2.0/dbhome_1

According to this oraInventory comes under the Oracle base directory.

On 10g documentation it states "The first time you install Oracle software on a system, Oracle Universal Installer prompts you to specify the path to this directory. then Oracle recommends that you choose the following path:
oracle_base/oraInventory
Oracle Universal Installer creates the directory that you specify and sets the correct owner, group, and permissions for it. You do not need to create it."

However on 11g documentations "The first time you install Oracle software on a system, Oracle Universal Installer checks if you have created an OFA-compliant directory structure with the format u[01-09]/app, such as /u01/app, and that the user running the installation has permissions to write to that path. If this is true, then Oracle Universal Instaler creates the Oracle Inventory directory similar to /u[01-09]/app/oraInventory. For example:
/u01/app/oraInventory If you have set the environment variable ORACLE_BASE for the oracle user, then Oracle Universal Installer creates the Oracle Inventory directory similar to $ORACLE_BASE/../oraInventory. For example, if ORACLE_BASE is set to /opt/oracle/11, then the Oracle Inventory directory is created similar to /opt/oracle/oraInventory."

Furthermore both on 11gR1 and 11gR2 documentation it is stated "Oracle recommends that you do not put the oraInventory directory under Oracle base for a new installation. However, if you have an existing installation, then you should follow the steps suggested in this section."

This change could be observed in the OUI installer when started with ORACLE_BASE vairable set the oraInventory location defaults to $ORACLE_BASE/../oraInventory.

ORACLE_BASE=/opt/app/oracle

10gR2

11gR1

11gR2