I maybe confusing things but,Iv'e exported whole mixes to a stereo .wav,without turning the soft synths to Audio or anything,I just choose export,and do it.
Sometimes, I get the "There is no Audio" to export,but if I save/re-open ,I can then export,a whole mix of a song,without any bounces,but I automate the master track volume,thats all.
I'm sure this is not the so called "correct way",but its working so far,again "my method" may have nothing to do with the topic......but it might,lol.
Bob.