I just happened to see some servicers wearing their company shirts while I was at immigration. Found them on Facebook, messaged asking price with money in bank already, and used them. Gives you price and if they speak/write English much and if they are attentive.
Given that, I found that the quotes are all within 1000 baht of each other, and they plus immigration was busy. Could be the last two weeks were 4 day weeks for them.