Hi Skoop @Skoopnox ,
First, let me get something straight; You can Add a Modifier and you can then Apply the Modifier (which also removes it from the Modifier Stack).
If you have a Cube , Add a Subdivision Surface Modifier to it, then switch to Sculpt Mode, you are Sculpting on a Cube (with only 8 Vertices).. You will actually have to Apply the Modifier, before you can Sculpt on the Subdivided Cube.
This means, that if you Add and Apply a Subdvision Surface Modifier, Sculpt a bit and then Add and Apply another Subsurf Modifier, etc., you can’t go back a Level.
Advantage Multires 😉
There are more advantages to a Multires Modifier; for instance, if you don’t Delete the Higher Level, you can adjust the shape of the model (by temporarily Sculpting on a lower Level), while ‘keeping’ the details you already Sculpted.
