I made some tests and here’s the result:
The first track is the original track with a effect applied.
The second track contains the bounced audio of the first track (Move Bounced Audio to New Track).
In the third track I have imported the audio file previously saved from the first track (Export Bounced Audio to Sound File).
As you can see, the levels of the three tracks are the same (peak and RMS).
I export my tracks to sound files
Do you export each track or only the master track?
The Export to Sound File… option from the File menu, exports the master track.
In the picture above, the level of master track is lower than the others. If you export it, the level of audio file will decrease.