Because no marriage extension is handled at the immigration office. They have to be sent to the district office for approval. That signature costs a lot more than the one from your local immigration office.
This is the reason marriage extension always has an "under consideration" period where you have to return later. Everything is sent to the district office.
For retirement extension, everything is handled instantly and locally.
Are you actually on the 90-day non-B visa, or are you on a 1-year work extension?
If you're on a visa, you cannot do anything except leave without a re-entry permit to cancel your entry stamp and then apply for a new non-O visa either from a Thai embassy outside of Thailand or from your immigration office after you return as a tourist, if your office allows conversions to non-O inside Thailand. This is because the first extension must be for the same reason your visa was issued for, so you cannot apply for a marriage visa or marriage extension from a work visa, you can only apply from a work extension to a marriage extension.
completely wrong. The airport is MORE of a problem. Hundreds of people per week are denied entry in Bangkok alone. And at least at a land border you can just easily return to the country you were entering from. At the airport you're put into detention until you can pay for a ticket to where they tell you that you have to go.
No one can give you an answer because it's up the immigration officer you're standing in front of. If they don't give you a warning the 2nd time, you'll probably be able to enter the 3rd time because they usually (not always) give you a warning before denying entry. Just make sure you have the cash requirement for entering as a tourist which is 20,000 baht or equivalent in another major currency in cash. And also have your flight ticket out of Thailand printed and available.
If they pull you out of line, expect to be interrogated for 30-60 minutes.
Yes. The 12 month statement is a base requirement for the extension. The credit advice is supplemental documentation that works on top of your bank statement to show the source of the funds.
I've seen the same report from others before. That once you change passports, you cannot use the online system until you leave Thailand and return. Doesn't really make sense, but what does in Thailand?