A ship destroyed should instantly count as undermining. It makes no sense to tie this together with turning in the vouchers.
That's what I was thinking too. Why not just credit the kill/cargo steal immediately ? It's the kill/steal that hurts the enemy, not the turn-in. Why have vouchers and turn-in's ? What is the benefit of that anyway ?
It'd be nice to have the stats show up on the galaxy map, though, so as to visualize it.