While true, flat and % physical are both usually lower than their magical-damage equivalents (although flat vitality is usually the lowest in the game, for obvious reasons).
Ceno’s tier list of damage types (best->worst) (a flat damage type may be ranked higher or lower in consideration of its DoT as well):
- Bleed
- Acid
- Vitality
- Pierce
- Physical
- Lightning
- Aether
- Fire
- Chaos
- Elemental (special case)
- Cold
- Life Leech