I couldn't agree with you more.  It is insane that there is an option for purchase order but you can do nothing the customize that purchase order.  It is useless for me to even create one due to the fact that when my vendor receives the PO, there are no quantities or prices listed.  I believe I am going to do a feedback to them everyday with this request.  Maybe they will get tired of hearing from me and fix it.  

I am glad I found your post.  I thought maybe it was just me and I didn't understand PO's lol.