Weekend Learning: ASM not starting after upgrade to 11.2.0.4

My Oracle Support article ID 2006534.1 has note "ASM fail to start with error ORA-00132 After Upgrade From 11.2.0.3 To 11.2.0.4" which has a very simple solution to the problem.  Now my next challenge is to understand why the spfile has to be modified in the way Oracle suggested!