17 Iyar (Behar-Bechukosai)

Why does Vayikra 27, 1-7, when discussing people's Erech, seemingly not go in a logical order? It doesn't go in order of age (but rather the order of ages is 20-60,5-20, 30 days-5, 60+) or in order of value (instead it's: 50, 30, 20, 10, 5, 3, 15,10). What is the logic of that order?