Kammas are imponderable?

Buddha says if one plants mango, he will reap only mango not something else. Short-lived and get killed are the result of killing living beings, poverty is the result of stealing, not trusted by others is the result of lying and so forth. Then why Buddha says the result of kamma is one of the four imponderables. Does it mean one who loves to kill living beings will experience poverty or not trusted by others which is the result of stealing and lying? How do we relate that with "sow apple seed, reap apple fruit?"