The LOS tool has some problems i would say. You cant see the LOS from "Upstairs" until you put a unit upstairs and select it, this should be changed so you can, in terrain that has a "Upstairs" level, always check even without putting a unit inside first. Also even when you put a unit inside that is upstairs and select it to check LOS for some strange reason it still checks LOS from Ground level. You first have to select the hex you want to spot and then point at the hex with your "upstairs" unit inside...then you can move the mouse a bit left/right to change between Ground and Upstairs level...this is confusing and not intuitive. Also the text "GROUND" and "UPSTAIRS" for the LOS tool always seems to overlap, especially with the "BLOCKING" text inside that hex.