Well if aliens raid a bank you will probably only loose the paper with numbers on it and be able to reprint it or to recover your debt data from backup copies since they surely will not use this money at the next burger shop or tank stop...
No real economic loss on this.
I think the maintenance cost per month should be higher since much of your cost depends on employees.
The cost structure needs a redesign anyway. I sometimes wonder why some weapons are comparatively cheap but one ammo clip has cost of a used ak47.
And $100.000 for digging a whole that big and a entrance with radar absorbing paint and other camouflage stuff? Can your guys build the public buildings in my country please?