I blame the high kill low xp on the fact that in general use the Pheonix gets most of it's vehicle kills on flashes (because it's one hit) and stationary targets like turrets (both engy and base) which yield the least xp of the vehicle kills. Mobile vehicles that take multiple shots to kill often can run out of the 300 meter control range of a pheonix before dying and repair yeilding neither kill nor assist xp. The rest of the kills come from lucky shots on wounded infantry which again tend to be lower xp than vehicle kills. Now if there was more coordination with groups of pheonix users I'd expect to see those numbers higher in general but lets face it, the majority of any empire is a zerg of rambos and the pheonix just doesn't get high xp kills without focused fire. A Lancer or Striker is more likely to tag a good assist on a tank/sundy before it exits range with a solo user, and the striker is more likely to get some assist xp on air raising the xp level without sending the kills into a similar rise.