3rd floor you have to report. Not ground level. They have the appropriate formulaic there. Although tm30 is normally for the landlord or owner to register you, you can use this also for registration.
why you are asked to fill in your address on the TM6 card everytime you come in the country? If they would put this on their database manual (not directly off course but lets say within 24 hours ;-) ), or better even, scan it and with handwriting recognition put in their database (believe me, those systems exist aleady), they could automaticly cross check this with the TM30 formular that every hotel and landlord has to send in, or the data known by immi already. All this can be done digital.
Thailand governement (police) is ahead of many things already. Like scanning and spying on us. They use same technology that the Chinese have developed. In China they work with face recognition. In Thailand also. I do not mind, i have nothing to hide really. It gets more scary if, like in China, the thai immi would scan any tourist all the time, reports all wrong things you do (like driving motorbike without helmet) and present you with a Bill or Penalty the moment you leave the country again. But, as we know, there is soo much data from these 30+ milj. visitors, it would take giant computers to keep reporting, updated and recognize all wrong things you do (which again China has, but not Thailand). The more data the Thai gov collects, then less chance that you get caught. Keep up the good work, gov.
the moment you come into the country should be the moment to update. Silly rule now is that if you have a visa or extension, you still have to go after coming back into Thailand within the next 24 report at immi...
"If you fly into Thailand and the Visa is still valid you get 1 year Admitted to stay. If your visa is passed the valid until date you need a re-entry ticket to keep your current Admitted to Stay alive" you stated earlier....
But non-OA comes with multiple entry, so no need to get another one.
Because you make your income in Holland and get paid to your dutch bank, there is no income directly from work in Thailand. You will have to pay tax in Holland and not in Thailand.
Tip : get your self a kvk as ZZP in Holland, and do every 3 month per computer a IB at belastingdienst.nl