User blog comment:Xilinoc/Ch. 638 - Boiling Malice and Total Comedy/@comment-10630156-20150806095642/@comment-1210805-20150806133235

That whole theory has so many holes in it. For a start, Mayuri using Quincy techniques stems from his studies of over 2000 Quincy subjects. The fact that he uses the name he heard from the Ishidas, and isn't sure if there's another name for it shows that it's simply something learned from his research.

Mayuri didn't even know about Letzt Stil until Uryū used it during their battle. He doesn't even understand what Uryū is doing at first.