https://www-secure.symantec.com/connect/forums/smp-71-sp2-point-fix-thread-updated-5712-v4
From a Symnatec employee (for SMP hotfixes):
"Rollups are basically a collection of Pointfixes. And Pontfix is a code change created to resolve particular issues of particular solution.
Latest rollup v4 contains all previous rollups (1, 2, 3).
But! (there is always but, isnt`it?)
Rollups don`t go through full suite testing as Service Packs do. Only solution based testing performed."