HA installation of SAP PI 7.1 on AIX with Linux Applicaiton Servers

In reading the note 1067221 I am not sure I understand it clearly. Is it saying that the first application server has to be on AIX and subsequent applicaition servers can be installed in Linux? Can anyone provide clarity to this please?

This is what the note says:

"Starting from an operating system on which the "first application server" is installed, you can - apart from installing further application servers on the same operating system (homogeneous installation) - only use one of the specified operating systems for a heterogeneous installation on the "second application server". The operating system releases are still only valid for the listed database systems."