Question for HERO Grognards

How much would play balance change if you applied the STUN multipler of killing attacks only to the BODY that penetrated resistant defenses? I'm noodling on the math of making a character comic book style bullet-poof (where they shrug off bullets with no effect, but get hurt by strong punches), and noted that the current HERO rules

a) apply the STUN multiplier before penetration is calculated, and
b) let you use non-resistant PD to avoid the STUN of a killing attack.

The latter makes it clear that the resistance is just needed to protect BODY, but the former makes it hard to really have comic book resistance to conventional (2d6 or less RKA) firearms while still be hurt, comics style, by other major non-killing attacks. I'm wondering if shifting the application of the stun multiple will correct that.

12 rPD vs 2d6 RKA currently will eliminate risk of BODY loss, but STUN loss after defenses would average out at 2 to 9 points but could swing to 23 or spike to 48! In order to get the feel I want I'd need a total rPD+PD of roughly 35 (enough to eliminate the stun multiplier of any average BODY roll), and with that the character is totally immune to an equivalent 30 AP 6d6 EB (max damage 36).

By reversing the order the 12 rPD would make the character immune to a 2d6 RKA for pretty cheap, but he could settle on a final rPD + PD of, say, 20, so the 6d6 EB would likely do a point or two of stun per hit. This is much more what I want, and gives a strong reason for Viper to outfit their goons with nifty little ray guns rather than conventional weapons.

Thoughts?