On the income issue, only once did I experience an issue with an embassy income statement, and I believe the problem was a new girl at KCI. Overall I have experienced that Thailand Immigration offices accept the Embassy Income Statement without issue (US Embassy).
But the 3 times I tried an 800K Baht bank statement I experienced issues at immigration. So I do not bother to try the 800K Bank route anymore as the minimal travel cost to the embassy overcomes any immigration hassle with a bank statement.
But that is just my view.