Let's also not forget that the aircraft you fly has a huge effect on k/h. The stat favors aircraft with big gas tanks and plenty of ammo. When I fly the 109G-6 I almost always have to rtb because of fuel before I can expend all of the 200 cannon rounds.
Still, it seems no one is willing to disagree with me that 5 kd, 1 ks, and e.g. 2 kh is more effective than 1 kd, 1 ks and 5 kh, and this example contradicts the agreed upon formula.
The 109K-4 is a very difficult aircraft to have a high k/h with. puujiiko, one of those crazy fins who flies almost nothing but the 109K-4, has a k/h of 8 with 172 kills, and that's about as effective as you can be in it.
I think I average around 7.5 kph in the K4 and I up at bases under attack all the time. I could get it a bit higher, but I also go off looking for 1 on 1's quite a bit which totally kills my kill's per hour stat.
Overall I pretty much think all the score data is useless when trying to judge someone else's skill level. There isn't a single item in the list that can't be manipulated by a score potato. Only thing score is useful for, is judging your own stats, because you are the only one who knows how you achieved the stats.