I have not been doing it long but I do commerical shreeding, dirtwork ,tilling, etc. I charge $45/hr or $25/acre. It works out about the same in most cases with my 6 foot shredder. Most clients want a per acre price because they know upfront what it will cost. The per hour scares them as they think you might milk them and make it take longer than necessary or at least that is the impression I have got.
Right now I have a $50 minimum on all work but am thinking of raising it. For example if I mow two acres and charge $50, it takes me about 30 minutes to connect the shredder, connect the trailer, load and chain down the tractor. Then 15 minutes to drive to where I am going, 15 minutes to unload, talke to the people, have them show me things not to hit etc, 1 hour to mow, the 15 minutes to load, chain down, collect money, and 15 minutes to drive home. So a two acres to cut took me 2.5 hrs and I made $50. Take out fuel for tractor and truck I made $40. Works out to $16/hr which ain't much when you consider wear and tear on a $20,000 tractor, truck, and trailer. $45/hr turns in to good money on larger jobs. I think a $75 minimum would be better and who cares if you lose the smaller jobs as there aint no money in them anyway.
If you can get $100/acre jump all over it. Non one around here will pay that.
$22/hr is way too low unless you are charging from the time you start getting ready until when you get home. I charge $45/hr from the time it leaves the trailer until it gets back on.