Paul, I was told on this group that I dont need to go out of Thailand to get non-O visa, just go to your local immigration office and they will change your current visa to no-O. Maybe another option for you too.
I already did some trips outside Thailand to get another 60 days stay. Last time I will enter Thailand on 4. Oct., so 60 days + 30 days extension = my stay is possible until 1. Jan.