If Serbia is within jurisdiction of Athens embassy why do you not apply before October 1st? Did you check the money is needed 3 months before? Certainly not all embassies need this.
the equivalent of 500 THB on a direct access bank account just is a visa requirement, which means Thai autorities are allowed to check.
That is not fear mongering, legitimate DTV holders have nothing to fear at all from checks.
And even illegitimate DTV holders do not have much to fear, because chances getteing checked ar less than a percent, but that still is higher than the chance you will win Thai lottery.
From an in-country trip you always need a new TM30 because the TM30 reported during your trip invalidates the previous one.
The 90 day report should be done within the specified period around 90 days after you entered and expires itself after 90 days again, and gives you the possibility to report around that expiry date again.
It can only be done online after the first one of the stay done in person, which means most DTV holders never will get that possibility.
The "after that" is only when you did first TM47 too soon, or do in country extension. Otherwise you only will do first TM47 every time you enter on a new 180 day stamp.
Anonieme deelnemer 689 Officially you need to be reported by the hotel owner/landlord every time again after you did stay a night somewhere else.
Some immigration offices make an exception in case you stayed outside the country and return to the same address before you left, but this does not look like an official rule.