@Magnus ********************
16,000 is that Baht? US$? £? if it's Baht, when was that, a few years ago? Who and where is the Agent? Several posts I've seen over the past few months, people are saying that Agents are charging 30k-60k Baht now.
As for "income letter/pension" as proof of funds, you should have also mentioned that getting an affidavit of income depends on what country one is from, because a few (or maybe more) Embassies don't do that anymore and for those that don't, using monthly Bank transfers isn't accepted until the second Extension of Stay.