rpm versioning

Recent (at least recently noticed by me) changes in the way Red Hat is
versioning rpms had an unexpected negative impact on some of our
custom packages that replace RHEL base channel packages. What we do is
a rather long story and not very relevant to my question which is more
about consistency and understanding what Red Hat is doing when they
version and re-version rpms they provide.

$ rpm -q --qf "%{RELEASE}\n" gnome-screensaver
6.el5

That is typical of how things have been and minor updates bumped
something before the .el5 bit.

$ rpm -q --qf "%{RELEASE}\n" cups
11.14.el5_1.6

This is showing up more and more and minor bumps are occurring after
the .el5 bit.

Rather than explaining how this affects the way I version packages
locally could someone just explain the actual way Red Hat is now doing
package versioning so I can adjust?

Thanks,
John