Paraeducator level I vs II & Sub Cert.

I recently completed my Paraeducator Level I Generalist Certification. I was considering adding my sub cert and possibly taking the special education area of concentration. I have a few questions.
My boss was adamant I can legally sub without the sub cert in Iowa once I have my para cert and said multiple paras in our building do. I have never heard of that before and can’t find anything agreeing with it.
Is this true or is my admin just violating the law?
Does adding level II really change anything in terms of what we can legally do? I know it isn’t going to change my pay and will be completely out of pocket. While gaining more knowledge is great I just can’t seem to find anything with regard to what it actually changes other than just being able to say you have it. Just trying to determined if it’s truly worth my time right now.