pkgsrc vs. binary packages

[Neal Hogan <nealhogan%gmail.com@localhost>]

<fromDocs>
"Basically, there are two ways of using pkgsrc. The first is to only
install the package tools and to use binary packages that someone else
has prepared. This is the “pkg” in pkgsrc. The second way is to
install the “src” of pkgsrc, too. Then you are able to build your own
packages, and you can still use binary packages from someone else."
</fromDocs>

This (as far as I can tell) indicates that one can install variations
between pkgsrc packages and pre-packaged ports ( i.e.,
"/usr/pkgsrc/xyz/ && make && make install" vs "pkg_add xyz) without a
problem.

However,

I have a  basic 5.1, i386 install and want to have a browser that has
flash 10 capabilities (ch 10 of the netbsd documentation). I can
install midori, xfce4, and vim no prob via remote binary (i.e.,
pkg_add -v xyz). It seems that nspluginwrapper is not a binary pkg, so
I attempt to install it via pkgsrc but there is a dependency
discrepancy (i.e., the version of, say, python, that pkgsrc wants for
nspluginwrapper is not the version that has been installed as a
dependency of another pkg install . . . again, the only other packages
that I've installed is vim, xfce4, and midori).

Is there an issue with keeping versions of pkgsrc-packages and binary
packages consistent? That is, why am I encountering dependency
discrepancies between packages?

-Neal