That armor value is the armor of that object itself. The cover is actually set in each entity (soldier). The 2x4_light_cover_light_crush only says it's cover type is "tp_light". The soldier in "ebps" has "cover_ext" and within also the "tp_light", which contains the real modifiers. So you have to change the modifiers in there for all soldiers one by one.
Safety_Value can't go higher than 0.5!