The best way to cope with certain aspects of this ask is it more than likely Common sense or in plain site on the Website from.which ever Consulate or Embassy your applying through ..
its Mr Wayne Billman that posted in the group think it was in BKK and submitted original paperwork plus more recent documents too from his employer & bank
(T.i.T) This is Thailand you could probably ask people that work in the same building at immigration and they'd end up telling you different information & prices....
Great to see quiet a few people have successfully obtained an Extension at Immigration now