SDOIT is similar to IT in the same way people argue that Outcry was like Metropolis. Even boiling down a 42 minute / 19 minute song to 7 main vague descriptions of sections it's a bit of a stretch.
However, looking at the rough structure of TCOT/IT, I came up with this-
TCOT
introduction of main theme in slower section > heavier instrumental section > heavy verse > chorus > instrumental noodly > different heavy verse section > chorus > instrumental > soft/ambient section > slower tempo epic finale vocal section at end > epic guitar solo outro
IT
introduction of main theme in slower section > heavier instrumental section > heavy verse > chorus > instrumental noodly > different heavy verse section > chorus > instrumental > soft/ambient section >
heavier vocal section > instrumental section > slower tempo epic finale vocal section at end > epic guitar solo
Is it a perfect comparison? Of course not. But there are actually a lot of similarities in structure, especially before the middle breaks. And while there are also admittedly some contrivances in my classifications, they're much less vague contrivances than yours!