Not all PTF's are in a cume or a group. Some never make it there. For
example, let's say I open a pmr and I'm the only one that experiences it.
It's not a critical performance, security or other type in that genre. IBM
fixes my issue by issuing a ptf. They may not put that PTF in a group
unless lots of others request it also. They do this out of fear that
their fix may have broke something else. They do not want to feed the "If
it ain't broke, don't fix it" trolls.
Also some PTF's have manual actions to perform. The biggest example is
WAS updates. Not only do you have to load and apply the PTF but you also
have to run through some other processes.