no, it's not. the volume faders are not adjusting the 'true volume' of a sound. if you want the true volume of an audio clip, consolidate it (which will automatically normalize it to 0db) and put the fader at 0. thats your true volume. the volume fader only adjusts volume relative to the incoming signal. so at 0 it just remains unchanged.

if you feed a sound that is -20db, it might be too quiet and you will end up raising ableton's volume fader past "0db", but just keep in mind that just because the volume fader says 2db that doesn't mean the sound is 2 decibels loud, it's just how much you've increased the volume of the sound relative to how it was initially.