It would perfectly make sense to have to show funds again for an extension. The opposite would be surprising as it would make the requirement when applying kinda moot.

As far as showing proof of funds for a report after a new entry (If I understand correctly the wording of OP) that's sketchy and maybe something has been misunderstood by someone or lost in translation.

Better source directly from the government:

@Mike *****

yes, anyone in the country can do it. Just submit the requested documents.

The annoying thing is the certificate of residence:

@Scotty ******

looks pretty in that color option 👍🏻

@Brenda ********

Lawfully, If you stay even 1 night at a family place , your family should do the TM30 yes. If you don't need immigration service, then up to you I guess.

But the rule is that any hotel, or head of household is required to do a TM30 for any foreigner residing at their place within 24h

You might get refused extension for that reason yes. I did see it first hand. Cheap option to make sure you're covered. Book a bed in a cheap hostel for a few hundred bahts and they will file the TM30 for you. Fill in the hostel address on your TM7 under place of residence.

@Rolf ********

And now you know the immigration place. Take the 800thb as an expensive guided tour 😁

@Rolf ********

Well if you got a receipt from IO for the 1300b, then the fine was no scam 👍🏻

@Rolf ********

if you didn't get a receipt for the fine from immigration (which should have been 1600b ?) then you were scammed

@David ******

but TIT, someone has to pay 😁 he was probably just scammed by the guy from the condo office... Paying him 800 says a lot. The fine being 1600b and not 1300b, I'm pretty sure something is fishy