Password files with RAC OneNode

My base question is, how does RAC OneNode (11.2.0.4+) handle the ora password files?  According to the documents I've read, such as notes 1922129.1 and 126728.1, with RAC the password file should have the format of orapw<SID>. Both of these documents specify the SID, and not the database name, for the password file name.  With RAC OneNode, if I have a database "MYDB", OneNode will spawn instances "MYDB_1" and "MYDB_2".  In this case, I would expect the system to use password files orapwMYDB_1 and orapwMYDB_2.  This doesn't seem to be the case; no matter which instance is running, the password