User blog comment:Xilinoc/Ch. 668 - BIGGER,FASTER,STRONGER/@comment-5657895-20160401172542/@comment-11293956-20160401194304

Volstandig is a Quincy ability and while Pernida and Gerard are Sternritter, them being parts of the Soul King might make them something other than your typical Quincy (like Askin or Bambietta) so it's possible that they don't have one. On the other hand, you may be right and they can't use Volstandig because its being blocked by their other powers (kinda like how Bankias blocked them)