Lawyers used to help, but now you have to show TOTAL income of 400,000 per annum . Can be a mix of income plus a deposit. But you have to show 12 months bank statements.
I think if you were due to do your report in February, you will get your stamp, but you will likely be fined 2000 bhat. The Amnesty was for 90 day reports due from March. I did mine two weeks ago as I missed mine for the first time ever, in January. I got fined. But got stamped ok. Beware, the 90 day report is now done somewhere away from Wattana