Brettski, for what it's worth: I had a similar experience with the soil and water department. The first lady came out and did a perc test and said no problem. After the house was built the original S&W lady retired and the new one said we had to do another test. The new lady didn't like the results so she said we had to install a curtain drain. My septic system was set into fill from digging my pond. It's pretty much nothing but clay with a little topsoil on top. One difference between mine and yours is that my fill was pushed in place with a track machine. It's been five years so far and we haven't had any trouble but I was taught that soil takes 7 years to settle, or at least before it's considered "undisturbed". In practical experience though I've seen it take 10 years to settle so I'll just be keeping an eye on my place.
Pumping would be a last resort for me. If I was in your shoes, I would continue to search for alternatives to mechanically lifting. Maybe the septic system installers will have some ideas.
