As I know PBGA reballing is not recommended or better not allowed by all the most important Standards. Exceptionally Cstly Ceramic BGA or Ceramic ColumnGA where you can perform electrical test before reballing (90/10 ball/column-balls made) some Customer allow it.
Reball plastic BGA it seams so simple operation to so why not ? But what about electrical test ? what about reliability after several heating times at +- 220�C ? etc ?
But you can say ; every body in the world make PBGA reballing!!!
Yes it is true, but right now no one (or very few) declaire it when delivering the product (PCBA) to the final Custmer.