Bobbie Stephenson I reported 7 days after here in bkk just last week, and was provided 90 days from the day I reported, not from when it was due. So I was provided an extra 7 days! I have the electronic printed receipt from immigration for the report, that also shows next due date as above.
Your "permitted to stay until"starts from entry, and you generally have 90 days from entry...depending if the particular officer gives you 90 days...as per your stamp you have until 6 Oct.
I know from the second issue, in Australia the Thai Embassy won't even issue a visa if you have less than 6 months on your passport.
You can get almost 9 months the same when you extend 30 days each arrival, I did on mine...60 + 30, 60 + 30 and 60 + 30 (last arrival must be just before visa expires).
Each to their own, but I prefer to spend 1 hour at immigration to extend rather than many hours travelling in bus to border bounce 🙂
The extension is added to the end of your admitted until date, not from the date you apply.
I'm not sure there is any restriction on the date you can apply for your extension, I believe it can be applied for at anytime after you arrive - someone else can confirm this!
I never said it was TM30, I said 2 different forms...the owner completes TM30 and the foreigner completes TM28, and you may be fined if you don't complete TM28