Sapperkenno, we might be talking about the same place. In addition to the headline rate on their website ($85.00 per hour) you need to factor in:
(1) Sales tax, which in the US is not included in the list price of anything, even at the supermarket
(2) Extra fuel costs. They reimburse for fuel you buy at other airports at the cost you would pay at their home airport. If you did short flights (no need to fuel while away) or checked around for the cheapest fuel at other airports there wouldn't be an extra cost. I was on a tight schedule and was focussed on seeing interesting places, so just fuelled where needed and paid extra for the difference in fuel costs.