Ah right, I didn't pick up this was a proposed explanation for a "fast" collapse.
Personally I think the entire "calculating energy required to break structure" line of reasoning is inherently flawed because it doesn't reflect what was seen on the day.
The collapse initiation led to a sequence of events that caused the structure to separate into component elements. The exterior columns peeled outwards (this was a force loading they were never designed to resist), and the core columns became misaligned by the twisting of the upper floors.
The upper section never had to smash through a lower intact section, because by the time the falling debris reached the lower section it wasn't intact anymore.
-Gumboot