On the L.A. Consulate website they have this under the submit Financial Document proof section. (Financial evidence: an amount of no less than 20,000 THB (e.g., bank statements for the last three months, sponsorship letter) It doesn't say anything about having 20,000 Baht on you as you pass through immigration. I'm taking it as having to show 20,000 in your bank account steadily for the last 3 months. I had emptied out that bank account to buy a car, but I forgot I have a Thai bank account with a few thousand dollars. So no problem there. I'm going for a multiple entry visa. I never saw this before either.
The difference in fee will not be refunded, if the officer grants a single entry visa instead of the multiple entries visa you applied for.
Guess it's how the officer is feeling that day. Would be nice to know why they would turn you down for a multiple entry.
Thank you all for your help. I appreciate it.