Well, Since posting this I called the pre-sales at web assist and was assured I can update the form using one of their extensions for Form building. Not sure how to approach this or if that is even true. Seems like she just wanted to say yes to anything to make sure I bought it.
I can't have people put PO (purchase order) numbers in the address field unless they update their profile every time they use the store (which is not realistic). Not a fan of putting unrelated data in fields that it doesn't belong in.
Most e-commerce experiences have a place where someone can add special instructions, comments and general information. Surprised Powerstore doesn't.