You're contradicting yourself. Assuming you can get the weapon up there DM to a 1/2" counter, you should be able to assemble and fire it. So for mortars smaller than or equal to 82mm, it should be legal.
Rubble location is not a building location. If it's not a building location, it can't be a upper level of a building location either.
No, I'm not contradicting my self
Upper Level Rubble
Location is NOT an upper level Building
Location as per B24.1
However, I see nothing that says an Upper Level Rubble Location is not part of the
Building or the
Building hex.
B24.1 says (with my emphasis) "A
rubbled Location is no longer a
building Location and a
building totally reduced to rubble is no longer considered a
building"
There is a difference between Building Location and a Building hex. B23.1 defines a Building hex.
Now I qoute B23.423, with my emphasis
"No weapon depicted on a 5/8" counter may occupy an upper level of a
building"
It says building, not building Location. The EXC is that Mortars are allowed on rooftops, but if an upper level has rubbled, there is no rooftop in that hex [B23.86]
Mortars can't fire from buildings because of the roof. What do you think fell down to create the rubble? (Hint, the roof and any floors above that level.) For VotG Gutted Buildings and RB Roofless Factories, there is no roof, and there is explicit allowance to fire mortars from those locations because they remain building locations.
VOTG rules only apply to VOTG. RB rules only apply to RB
Now I happen to agree that Mortars should be able to fire from upper level rubble Locations from a reality POV, if you are able to get the Mortar up there (eg in its dm form). Hoever at the moment B23.423 does not seem to permit it. You can take the dm Mortar up there but you can't assemble it to its 5/8" form. The 5/8' counter is the key, which is why I say a SW Mtr can fire from an upper level rubble Location.
Cheers
Jon