GBPNZD and Elliott Wave Principles

Wave 2(Blue) was a Zigzag and we should expect a Flat for Wave 4(Blue). After Wave 3(Blue) completes, a lunge to the downside occurs and this is our Wave A of the Flat. We are on the Wave B(Black) of a Flat as Wave A(Black) has already completed. Our Wave B(Black) should go beyond the end of Wave 3(Blue) since it is a Flat.