I will be leaving Thailand soon and traveling for six to eight months. I'm currently here on a non immigration type O extension of stay that lasts until October 1st 2019.

When I return to Thailand next summer I want the ability to extend the non-imm. Type O visa for an additional year until October 2020. Let's say I apply for this one-year visa extension 30 days before October 1st or September 1st 2019. Can I move the 800k Thai baht out of the country now and then transfer that same 800 K Thai baht back into Thailand by June 1st 2019? That way I would have 3 months of 800k thb balances on my Thai Bank book when I apply for my one-year extension on September 1st 2019. Is the bank obligated to make a note on the documents that I did not have the 800k Thai baht balance in the country for the first half of 2019 and thereby creating an issue when I take those documents to immigration?

Or should I instead keep the 800,000 Thai baht required balance in my Thai Bank. I would like to move the money out of Thailand because I do not want to fill out Thailand tax returns for the 2019 tax year if possible (in the event I choose not to return to Thailand) and I would like to earn 2% interest back in my home country in my high-yield savings account. However the cost to move the money out of Thailand for 6 months might come at a great cost because of the associated wire transfer fees.

I used Transferwise on the incoming 800k Thb transfer and the fees were about 1% from what I remember. But, there are higher fees outbound because apparently Transferwise does not currently have the ability to transfer money out of Thailand. To move the money back to my home country using Bangkok Bank I would have to deal with the fees and markup of exchange rate at Bangkok Bank and an intermediary Bank which could add up to 5 to 7% fees on the amount transferred. In addition, if I moved the money back in June of 2019 there are the roughly additional 1% transferwise fees to move the money back into Thailand on June 1st in time for the September 1, 2019 non immigration visa extension application.