Good answers.  One problem though.  20mm does not equal a grenade.  If it did and I put one in your plains tail or wing you would go down.  It takes several 20mms to kill a plane.  It takes a couple hitting several feet away from a target to kill it.  Thats not right but we have been down this path before, so I will drop it.
FYI, there is a ground effect on 20mms.  Next time you try to vulch try this.  Fire a few rounds close to theplane on the ground.  Do not hit the plane.  Just a very short burst close to it.  Next, try hiting the plane with the same number of rounds and see the difference for yourself.
In anycase, I don't mind a few easy kills by not having to even hit my target 
