尝试在E中以相同的净额计算增值税，但答案不正确

I tried to use code to calculate VAT and Total in the same Line E (same line as net amount), but the answer of VAT is much higher than 20% of net amount. Same problem with Total amount. I think these two figures might pick up some other figures rather than just net amount. Here is part of my code below, could you please give me some advice? Many thanks