Niten Ichi-Ryu not working with Ironshod / Powered Quarterstaff

0.C Stable
Windows 7 64-bit

I’m not sure if this is a balance consideration or an oversight, but the Niten Ichi-Ryu style works only with regular quarterstaves, but not with Ironshod or Powered varieties. I can sort of see the case for Powered being too awkward/modern/whatever, but it’s strange that simply adding two iron bands makes a wooden pole unsuitable for martial arts.