With regard to what you can do, there's no difference. So sure,
you can "get round" the 2 remote admin connections this way.
BUT: it will mean that you need to install and activate a TS
Licensing Server and you will need to buy and install TS CAL on it
(sounds as if you have already done that?) for every user or
device that connects, *also* when you connect as an Administrator
to perform remote administration. So it comes with a cost.
Another drawback is that installing full-blown Terminal Services
changes the internal tuning of the operating system quite a bit.
If you run other server software on this server (Exchange, SQL,
etc), expect to see a drop in performance for those tasks, even if
you don't have many users connecting to the TS.
Installing software on a TS is also quite different from
installing software on a "normal" server. When you install
software on a TS, a lot of registry changes are made to ensure
that multiple users can run the same application simultaneously,
with ech user getting their own settings.
This doesn't have to be a problem in itself, but it usually means
that "toggling" from full-blown TS to Remote Desktop for
Administration and vice versa, forces you to reinstall all
existing appplications. So you really want to make up your mind
about this before you go on.
If you continue with this setup, also make sure that you configure
the rdp permissions in such a way that normal users cannot start a
TS session to this server.
Further background reading:
252330 - Toggling Terminal Services to Application Server Mode May
Cause Programs Not to Work
http://support.microsoft.com/?kbid=252330
186498 - Terminal Server Application Integration Information
http://support.microsoft.com/?kbid=186498