There was nothing in the "Remarks" section at the bottom of the page? The one time that I got the "rejected" result, they explained what they were unhappy about in that area.
A friend of mine used a letter like that a few months ago and it was accepted, but it probably depends on which embassy/consulate you're dealing with, and perhaps even the individual officer who adjudicates your application.
The requirement for the US is three days (not 72 hours) prior to departure from the point of origin, and the three-day period applies to when the sample was taken, not when the result came back. From the CDC:
"'Why does the Order specify 3 days rather than 72 hours? What is considered 3 days?'
The 3-day period is the 3 days before the flight’s departure. The Order uses a 3-day timeframe instead of 72 hours to provide more flexibility to the traveler. By using a 3-day window, test validity does not depend on the time of the flight or the time of day that the test was administered.
For example, if a passenger’s flight is at 1pm on a Friday, the passenger could board with a negative test that was taken any time on the prior Tuesday or after."
A friend who arrived last month had his flight delayed for several hours, with the result that he arrived in Bangkok well after midnight and didn't arrive at his ASQ hotel until after 5am. They still counted his original scheduled arrival date as day zero, and his quarantine period was not extended by a day.
What will you use it for? If you plan to use it to register a marriage in Thailand (not really possible at the moment due to entry restrictions), be aware that the Thai authorities will only accept a self-serving affidavit executed at the US Embassy in Bangkok or the Consulate in Chiang Mai. They won't accept any document from the US, even if it is actually more useful in determining your marital history.
I've never asked Schwab to raise my daily limit, since it's never really been a big issue for me. The $1k limit meshes with the 30k baht ATM limit (at Krungsri, TMB, CIMB, and Citibank ATMs), so an increase would only let me make multiple pulls in one day, rather than getting more in one pull. That would be slightly more convenient than, for example, having to go to an ATM three days in a row if I need 90k baht, but that's not too big a deal for me (and the extra trips to the ATM at least get me out of the house :) ).
I've also never tried a counter withdrawal, though that seems more interesting if I could really get $3-5k at one shot with a single fee or no fee - I've just been too lazy and complacent to try, especially since my ATM fees are reimbursed anyway.
I have yet to try Transferwise, either, since - as you rightly note - it's more expensive than withdrawing from an ATM using a Schwab card. It does seem to have the advantage of being quick, and allowing moderately large transfers without having to undergo the telephone security interview that my credit union conducts every time I do a wire transfer - which is why I've only done SWIFT transfers for very large amounts (like my 800k extension deposit), where that's the best and cheapest way of getting the funds over here. Transferwise clearly has its uses, but a lot of people have been blinded by its shiny headline exchange rates - which you can never actually get, or even approach - into thinking that it's better than it really is.
I personally have never been asked for a copy of my TM-30 receipt or my lease when extending my Non-OA and then Non-O at CW, though I always brought them along just in case. I don't know whether this is somehow dependent on the circumstances of the individual applicant, or just on the whim of the officer.
That isn't correct. The rate you get at an ATM will be the Master or Visa rate, even using an ATM card - the TT rate of the bank that owns the machine never comes into the picture. I've been getting pretty much all of my baht cash from ATMs for over five years using a Schwab debit card, and can confirm that the rate I get each time is exactly what is shown on the Visa website.