A one year extension to my visa type may be requested during the last 30 days of it’s validity. That starts soon. Each regional office implements the national requirements as they see fit, usually by adding more hoops to jump through.
Today I visited to find out what I needed to do. There are two non-trivial items. One means another visit to the US Embassy. The other is waiting until 20 days left on the visa before applying because of the time elapsed since transferring funds from the states to my Thai bank account.
Should I not wish to wait those 10 extra days, paying 4000 baht (~ $127) makes that problem go away.