Suave, which name are you using when you fly? I tried looking at your scores using "Suave1" and "10buck2" but no scores are shown.
Anyway, Pilot Score shows "all" deaths, including crashes/deaths where no enemy was involved, whilst Kill Stats display deaths due to enemy fire only.
Example:
My Pilot Sore is 31 kills, 12 deaths
My Kill Stats are 31 Kills, 11 deaths
This shows that I was shot down and killed 11 times and once killed myself when crashing.
Effdub