So do you have something you can show the embassy to prove your income. I guess something sourced from Australia, but your Thai bank account may suffice.
He wants to do income and not money in the bank. You need to go to your embassy. It looks like you are Australian. So am I and have a retirement extension based on an income letter. You just go to the embassy and write out a stat dec and provide something that shows where the income is sourced from. This is a new requirement. Maybe your Thai bankbook would suffice or some statement from Australia. Say a payment advice from a real estate agent if you're living off rent, etc. The stat dec only needs to be a few sentences. The embassy has a sample of the preamble that you need to state. I think the fee is 500 baht.
O-A Visa granted in your home country. Slightly more difficult to get as you need a clean police report and a medical saying you don't have a few weird diseases. See your home country Thai embassy website for details.
What would they have to gain by tampering with visa requests. They are paid a commission on handling the paperwork and liaising with clients in the local language prior to submission to the embassies. They are paid if you pass or fail. I don't get it?
I've got one 3 times at BKK with no problems. Make sure you have a photo as sometimes the photo machine is broken and they send you back outside to get one. Usually they just do everything for a 200 baht compulsory fee. It's up to you to weigh up the risk of it not being available and losing your permission to stay vs time at immigration.
Technically they are incorrect because it doesn't mention during the validity period. It gives a blanket statement that there is no need for a re-entry permit when one may be required during the final stay previously mentioned in the article. Anyway I just think it needs clarification. But up to you.