1.3 INDIRECT FIRE TEM: Units subject to Indirect fire, OBA, NOBA, Aerial attack, bombs, and Napalm attacks while located in the topmost level of a Roofless Building may not claim the additional +1 DRM since there is no "intact roof" above the topmost level. They do receive the +3 TEM for being in a Stone Building.
Here is where my problem stems. Units on the top floor (level 1 here) of a stone building, with a roof, do not get an extra +1 for the roof, only +3. This is normal. I'm not certain if Corregidor is intended to act differently and there is at least one roofed building on the map. Units on the ground floor of a two level building get +1 for the level above and I believe this would still be the case for roofless buildings on Corregidor as per the example. "A Japanese 4-4-7 squad at ground level in Roofless Building hex GG11 is subjected to an OBA attack. They would receive a +4 TEM to that attack (+3 TEM for Stone building and +1 TEM for the floor between Ground Level and Level 1 ".
This being the case, there is no difference between a normal stone bulding under OBA fire and a roofless one. That may be what was intnended and if so, fine but then the whole section is not required.
My suspicion is that the intent was to make units in a roofless building ,more vulnerable, but the rules do not do this.
Secondly, can you place a 5/8th counter on the upper floor of a non-fortified roofless building?
1.2 All stone building rules apply normally except as amended herein. Contrary to
C2.7, both AA Gun (≤ 20mm) and Mortar (≤ 82mm) fire is allowed from within a Roofless Building as long as the AA Gun/Mortar is located in the uppermost level of the Roofless building. Mortars on the topmost level of a Roofless Building or in the ground level location of a Roofless single story building may use Indirect fire as if they were on the roof (
B23.85).
C2.7 PROHIBITED HEXES: A Gun cannot occupy an upper building level
[EXC: Fortified Buildings and mortars on Rooftops], nor can it occupy a Water Obstacle, crag
[EXC: mortars; B17.4], marsh, or Irrigated-paddy (
G8.12) unless dm and possessed or in/on a vehicle/boat. Small-Target-Size Guns and AT/INF Guns that are not large targets are the only 5/8" non-vehicular Gun counters that may ever occupy a building/rubble hex
[EXC: Rooftop mortars (B23.85); Fortified Building (B23.93)].
I think you can but wish it had been specifically made unambiguosly clear.