The local Immigration offices have their own requierments, hence it can vary...
The link you added was to the Immigration Office in Nonthaburi. If that is the Immigration Office where you will do the extension, I would rely on that information.
maybe no one answer the question because they read the requierments and actually understood the meaning of this: "It is important to note that you are only able to apply if you are currently not in Thailand..."
Also, one requierment is "document indicating current location". This can NOT be Thailand.
Do you keep questioning what everyone has commented so far, because you don't like the fact that applications should be made from outside Thailand?! 🤔
you are starting to look ridiculus. C'mon, it's an advice group! 5 comments saying the same thing... did you try to look for that information there yourself? No, didn't think so, since it isn't there!
You can search for information in this group... I just did a search for "Jakarta" and the 2 first posts that showed up had gotten approved in 2-3 days. However that is no guarantee, they could ask for additional documents and so on, making it take longer time. If it were me, I would not book a return flight until after my application got approved (but that is me).