Thanks for your reply.
Well, the immigration office asked me for my marriage certificate and birth certificate when I was there last time (at the end of 15 months use of my Non-O visa based on marriage) when I was applying for a 60 day extension.
Then then told me that the needed the mentioned documents to do that but later my visa agent told me that there was no 60 day extension and I would not be able to extend my visa for 30 days but needed to leave the country (which I did). Thus my confusion.
So, if I understand you correctly, I can now extend my stay by 30 days and after that extend my stay by another 60 days, is that correct?
And which documents do I need aside from the form?
Thanks again