According to IPC-A-610 Rev. E chapter 126.96.36.199 "BGAs" 30% Voiding is okay. In very level. So normal industry standard. There is no solderpaste reflowing without voids. And voids are not automatically a problem. That is the reason why production and customer are allowed to negotiate a own border for that value. Head-In-Pillow-Defects were be a problem. But you have to lower the x-ray angle to see them. So from that Picture: Everything is fine for me.