A clarification about stunting in ICONS

SYSTEM: ICONS

So over on Facebook, I asked, in a long-winded way, this:

Looking for a clarification here.

Do extras on a stunted power cost additional Determination points or Advantages? (That is, stunting a power with an extra costs 2 DP, and requires two Qualities activated.)

The situation is that I was playing a phased character, and I wanted to simulate the gag of "hurt someone by turning solid inside them." I figured I needed to stunt the Blast, so that was fine--I had one Determination point, so I stunted off the Phasing and had a Quality that was appropriate. But I needed the "Affects Solid while Phased" extra, and I would have liked the "Burst" extra as well. (I was looking for a way to destroy an item from the inside.) So I needed to stunt a complex power: a new power with two extras.

• Does it require three DP/Advantages to do this? Or just one, stunting a power will the extras involved?
  
  In the moment, I spent the DP, did a maneuver, and took Trouble for the last one (because I failed the second maneuver roll--I stunted Slashing instead of Blast, and took damage from the explosion.
• Do Limits offset Extras when stunting a complex power like this? (Normally, a stunted power lasts until the end of the chapter, according to my imperfect memory, but I guess you could make requiring a new stunt/DP into a Limit for this purpose.) Inventing Limits didn't occur to me in the moment.
  Also, if it requires multiple DP/Advantages, they have to activate separate Qualities in order for them all to go off in the same panel, right?

And Steve Kenson answered back:

Generally speaking, the answer is no, stunts involving powers with extras generally don't require a character have advantage more than once or cost more than 1 Determination Point, although the GM is free to make exceptions for extremely powerful or unusual stunts. In my opinion, worrying about balancing all of the "moving parts" of a stunt is more work than is needed in the midst of game play.