@Da***
, the O in a Non-Immigrant Type O visa stands for "Other" and it is a category of visa they issue for being over 50, being married to a thai, being married to a foreigner who legally works here, taking care of half thai or foreign children here and volunteering.
You could use the income affidavit at a thai consulate in the area to get a 90 day Non-O visa, BUT they will take the affidavit, meaning you'd need another one when you apply for the year extension inside the country 60 days later..
Any way you slice it you're not going to break either the 14-21 days under consideration to get a Non-O inside the country (if you get the Non-O at the immigration office) OR if you got one from a thai consulate you're not going to break the time line where you can't apply for a yearly extension until you have 30 days or less left on the 90 day stamp you got stamped in with.