Agreed. But for the renewal 1 year later, if transferring the equivalent of 65k baht/month for the past year, that evidence will get you the renewal and you no longer will need to have the 800k in the Thai bank. Also, during the 1st year, the 800k isn't untouchable. You can use up to 400k. And IF married, it's 400k not 800k and evidence of 1 year of transfers of 40k baht not 65k.
For International calls only, no need for a SIM. Go online and look up yolla.com. VERY cheap to call the U.S. or wherever. I can call Internationally from the U.S. too..and very cheap(not necessary that much nowadays if your friends/fam have the same Social Media website to call(FB, WhatsApp, Viber, etc).
Big financial meeting in Thailand in mid-Oct. Hope they lower interest rate. Would be smart for them to weaken the Baht some right before high season for tourism