Could you explain that method please? Sounds interesting
You start by duplicating a certain track that needs more bounce or punch.
You then put an expander on both tracks with a neutral setting on the first track so the plugin only stands as a compensation delay so both tracks don't go out of phase.
Then on your second track you adjust the expander's settings so you accentuate the peaks in an almost apparent way.
(ex: Attack around 220 us to a couple of ms, Hold around 80 ms to 130 ms, Release between 700 ms to 1.5 seconds, Ratio between 1.01 to 1.5, Range between 4 to 16 dBs and the Threshold at 0 dB so it's constantly working on the dynamics.)
Then you can mix both tracks together and your able to add dynamics in a paralel method by simply raising the duplicated track's fader.
You can sometimes add a compressor on each track as one is at a neutral position so it can still work as a compensation delay and the other one will work on compressing what you previously accentuated with the expander.
You then need less compression to get the punchy sound you wanted and if your compression settings are well set, the result will be overly punchy for that duplicated track.
(Ex: Attack around 100 ms so the peaks wont get compressed, Ratio being less than 2.5 sometimes more around 1.8, Release to taste and a treshold that always makes the compressor work around 2 to 4 db's of compression)
You can finally mix that overly punchy duplicated track with the original and you'll get a nice control on how much fat and punchy you want your track to sound while still being able to automate that quantity of punch troughout the song to make those quieter bits sound untouched and those louder bits sound more controlled but still fat and punchy.
You can also seperate expansion and compression on different tracks too if you want by having 3 identical track working together with one having both plugins at a neutral position and the others having one of both plugins at a neutral position. You can than control the volume between the original signal, the compressed signal and the expanded signal.
Good luck! Have fun and feel free to try this in every situation where you need to work the dynamics of an instrument or a whole song without compromising (processing) the original signal.