I have a suspicion that you need new lawyers. Having two different processes for two very common licenses seems a little off. The two cases aren't that different, legally.
The GPL does require some extra work, but it's on the technical side, to make sure you're shipping all the source that you need to ship.
Just a single outside lawyer we consulted with :) We already had processes in place for dealing with BSD.
The reason for consulting with a lawyer was to ensure that we didn't do anything wrong which would later require us to open up source code that we didn't want to open up.
The GPL does require some extra work, but it's on the technical side, to make sure you're shipping all the source that you need to ship.