Is an Affidavit Of Service required to make a POA valid and complete

No.  Affidavits of service have nothing to do with the validity of the document which was served, They merely attest to the fact that the document was served when service is necessary.  For example, a Court order may be perfectly valid, but you can't hold someone in contempt for violating it unless you can demonstrate that they had notice of it, i.e. were served with a copy.