When should I use Trim vs. [Move vs. Scale] Vertically?

Some pretty dumb/newby questions to follow, thanks for your patience and any help … :blush:

  1. Is Trim is the same function as “Move Vertically” (page 231)? Are they are both like “pulling down the fader”?

  2. Understanding the manual says “Move Vertically” just adds or subtracts dBs to the points, but “Scale Vertically” raises or lowers the values in % not absolute values:
    – What exactly does that mean, to “raise or lower the value in %”? If I have two points, at -3dB and at -2dB, and I lower them by 50%, what is the final value of the two points - 1.5dB and 1dB?
    – What if I RAISE them by 50% , what is their final value?

  3. Musically - what kind of situation would I choose one of these three automation (Trim; Move Vertically; Scale Vertically) options over the other? If I want to make a chorus softer … I just figured that would mean to pull the fader down … why would it be musically better to change them by a % instead?

Thanks much for any help!