damage of planes to buildings

Undaunted wrote:

why planes give same damage to all buildings ?

for example give 5 damage to unprotected factory or infrastructure and give same 5 damage to fortification who includes durable concrete

I know fortification has more health point but they are totally different buildings

Bombs hit concrete and iron all the same, bombs aren't picky with targets, maybe more bombers bombed the fortifications than the factories, hence 5 damage per.