Forex Elliot wave theory confusion

Hi guys. I want to ask a question about Elliot Wave theory. In books about Elliot Wave, we always see that a 5 wave up followed by a 3 wave down. And in these 3 waves down, we have wave A and C comprise of 5 waves and wave B comprises of 3 wave. If it is true then a correction will always be zigzag (5-3-5), which doesn't make sense! Can anyone explain it to me? Is wave A necessary to have a 5 subwaves down ?

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