Industrial Powerhouse and Building:Other

I am making a map. I made a simple fortification unit under the classification Building:Other because I don't want it to have the +1 DEF bonus of a Building:Defence .

Problem I found out recently is that the Industrial Powerhouse strat makes Building:Other cost $0 (free), ruining the scenario balance. It is done this way because in World Map, only Radar Array and Naval Battery is Building:Other, so it's good that its free with that chosen strategy.

My question is if I change it to Building:Defence, and it has a high DEF, it means it will be first defender of any battle in the city, meaning it will be killed first. So please answer this: if it is killed first, will the +1 DEF bonus to all other units in the city disappear once it is killed during a battle?