IO believe the difference is that an install will only install parameters related to "drive application". This would include things line motor nameplate data, max and min speeds, accel/decel rate, function block linking, etc. A full install would download all the parameters from a standard install but would also install what are called "frame dependent" parameters such as drive drive max current and drive voltage rating.
I have only done a full install a couple of times and then only when told to do so by SSD. I'm pretty sure you can get a drive control section pretty unhappy if the frame dependent parameters don't match the actual drive power section.
Keith