Bear with me a second here, I'm not an expert on demolition by any means but if this unconventional method that you keep referring to is so effective (as seen by the WTC supposedly achieving freefall speeds) then why isn't it used more widely i.e. it becomes the conventional? Like I say I know little about demolition but in most industries you find the most effective techniques tend to become standard frequently provided they can be implemented at a reasonable cost.
Or to put it another way, it seems like a heck of a lot of effort to go to - ploughing a couple of jetliners into the WTC Towers when you could simply use these unconventional techniques to achieve the same result with much less hassle.