Reply #79: And the ASCE report is using tail height while resting on wheels.

[Bolo Boffin]

This is from page 32 of the ASCE report:

The height of the damage to the facade of the building was much less than the height of the airplane's tail. At approximately 45 ft, the tail height (with the aircraft resting on its wheels) was nearly as tall as the first four floors of the building. Obvious visible damage extended only over the two lowest floors, to approximately 25 ft above grade.

I don't think the ASCE had the Morris picture, RH. It's not in the report, and their only reference to facade damage was pictures taken before the collapse. But you're exactly right. That white mark is where the tail fin would have struck, at the right angle, and the right height when the landing gear height is subtracted from the tail fin height. Good find.