Welk sorry..but IMO abd 35 years experience Immifration id the only one who can deal with each persons individual situation. Only they know your situation. 1. Agents want money..dont kud your self they are helping you
2. Each person is responsible for yourvisa being correct - NOT the agent.. If there is a problem - its your problem...
3.In the past agents have been arrested for a) providing false information and b) using fake stamps to provide (illegal) visas.
So..like i said..its up to you. if you want to take the risk..Good luck.
Good luck..IMO its best to get it from the horses mouth. so you know exactly where you stand.. Be very nice..ask for their help...beg if necessary .. . Thai govt officers like to show they can help in these situations... just no "foreign" anger.. I am sure they can help you.