The below colum is from the M&M preview as I'm sure you know and is regarding Damage, hit points do not seem to come into it at all, or even get mentioned.
DAMAGE TABLE
Damage Save …Stun Damage Lethal Damage
Succeeds No damage No damage
Fails Hit Hit
Fails by more than 5 Stunned Stunned
Fails by more than 10 Unconscious Disabled
No damage:The target shrugs off the attack without
any effect.
Hit:The target suffers a minor hit.Every stun hit
imposes a –1 modifier on Damage saves against further
stun damage.Every lethal hit imposes a -1 modifier on
Damage saves against all forms of damage —both stun
and lethal —since it represents a more serious weak-
ening of the character ’s resistance.This penalty is
cumulative with the penalty for stun hits.So a character
with 4 stun hits and 3 lethal hits suffers a -7 penalty to
Damage saves against stun damage and a -3 penalty to
Damage saves against lethal damage.
Stunned:The target takes 1 hit as above and is
stunned for 1 round.The character cannot take any
actions (including free actions such as sustaining
powers)and loses any dodge bonus to Defense.
Attackers gain a +2 bonus to hit stunned characters.
Unconscious:The character is knocked out,
effectively helpless.
Disabled:The character is conscious and able to act but
terribly injured.He can take only a half action each
round (either moving or attacking,but not both),and if
he performs any strenuous action,his condition changes
to unconscious after the completing the action.
Strenuous actions include moving,attacking,or using
any ability that requires physical exertion or mental
concentration (including most powers).