We all know that the price of 22k baht paid by the OP is high but the agent is going far and beyond.....
'I didn't know location was an issue. I NEVER go there, she always comes to me, or meets me at the immigration office'
Not too many agents will come to you, so I reckon the 22k is on the money.
You are paying for the convenience, some people have difficulty in travelling, mobility is an issue, so having an agent come to you is going to cost more.