Give grens points for killing a vehicle by flip. pros: more accurate point dispersal cons: the shame received for getting flipped.
Flipping vehicles isn't a good thing, if vehicles are supposed to die from that many mines then make mine damage stack exponentially, if they aren't supposed to die from that many mines, then get rid of flipping and certainly don't award points for it.
Giving points for that would be a bit harder unless you hit them hard enough to do damage to them right before they fell off.
Would you get two points for causing a tank to do a barrel roll? Extra points for pressing Z or R twice?
you'd have one hell of a time trying to get a barrel roll, so you'd get infinite points if you could pull it off