Re: Mite count
It appeares that you rather urban and more or less bee isolated location is a good one for keeping mite loads low. I think you should expect what you have experienced. Keep doing what you are doing.
I read Randy Oliver's most recent article in the ABJ. You might want to read it too. He points to changes in agriculture for our decline in colonys. You don't have that problem where you are, so maybe being where you are helps.
"Most of my exercise comes from wrestling with pigs and beating dead horses."