I submitted my application on 9Jan . Approved on 5 Feb. In between they requested me to explain why I have a Thai bank account. After my explanation email, the visa was approved in 3 days. Hope this helps.
Application is done online. Doesn't matter where you are now as long as you have a permanent residential address in the country of application n fulfill the conditions.
I was in Thailand n apply thru Singapore Thai embassy, providing all my documents, appt letter from Singapore co., bank statement.
I presume you have a Thai bank account. If you present your Thai bank statement for your DTV application, they may ask you for an explanation letter. I was asked for such letter during my DTV application.
After the huge money laundry case bursted in Singapore, all Asian countries are very strict in Bank account, especially if you have multiple accounts. You are on the suspicious list.