I'm not disputing how much you lose, I'm saying you don't get an extension. The seven days runs from the date the application is denied, it's not added onto the existing visa. Better to put the money towards a border run, much more effective and no unsavoury stamp in your passport
Which is why I said "technically". You pay for an extension which is not approved and you forfeit the 1900 baht. Amounts to the same thing but you get an unsavoury stamp in your passport which can affect visa applications to other countries. Russia for example will not issue a visa to someone who's been denied a visa in another country
Technically not. You pay 1900 baht for an extension, which is denied, so you lose the 1900, and are directed to leave the country. It's non-negotiable and you cannot move onto any other visa once that denial is issued
It's not a 7-day extension. It's actually an "extension denied" stamp - and you're ordered to leave the country within seven days. Not a good stamp to have in your passport
If you continually do it without having reasonable periods outside the country, eventually you'll be first interrogated as to why you don't have a proper visa, and eventually denied entry and sent away.