I almost have beta 4 ready and will go over the heli scripts tomorrow just to be sure. But if I see something wrong the fix will go on the new one.
And just to clarify, it is impossible for a helicopter to see through solid walls. Always been that way mod or not. Doesnt mean it stops bullets if the heli is firing at someone else and you happen to be in the line of fire or behind the target.
For ceilings there might be one deliberate exception I can think of. It is due to the mapper not making them solid. An example of where a mapper might do this is a cave map or a cell block with no open areas. The top must be non-solid or airstrikes and helis would be useless. Sometimes mappers want them to be useless. Other times they want them to work.