Seems to me that your way involves a lot of messing around. I've installed literally hundreds of 3rd party aircraft to CFS2 since it was first released. In all that time can only remember two that I couldn't get to work within a couple of minutes. That seems a far better success rate than yours.

The point is that aircraft can be listed on the Mission Builder menu even when they're incorrectly installed. If an aircraft is not listed on the Free Flight selection menu you know immediately that something is wrong & you can investigate. You can also give it a test flight to see if it's suitable for use in a mission. Many aren't without a few tweaks.

In the end it's a matter of what you find the easiest.