Applying automation to song: bounce or mixdown?

[Pericles]

I wish to apply an automation to the song as a whole, not on an individual track. For instance, a LPF sweep or speed up a portion of the song. Would mixing down (I don't have any FX on the masterbus) and reimporting as a new track and applying the automation to that track be the same as bouncing down all the individual tracks to the single track and applying the automation to the new bounced track? And would I then mixdown this new track (with the automation) to then be sent off for mastering? Thanks.

[mschenkel]

Wut?
If you mix down with master/global automation you could avoid a second mix down.
As far as I've understood you have a already mixed and almost ready for mastering tune but for let say a filter sweep on the whole mix.
I would proceed like this: mixdown the entire tune, reimport and add the sweep to the track and mixdown again
OR
Add the filter to master, record/draw the automation, mixdown.
The results should be the same