Congrats on the biz and welcome to the site.
Not enough information to be sure. I think you're maybe a bit low sometimes, but you seemed to have had a good year....must be doing something right. Every area can be a bit different. Even so, I'm figuring that, with two other guys, you're not using everything at once, right? Second chipper is a spare? Only using one truck at a time mostly?
For Example:
I have a Ford Super Duty that is taking the place of my old Chevy one ton this year, but I'll keep the old truck as a backup, or a spider lift pulling wood hauler. I'll probably still have it when I get my bucket. I'm also in the market for a second chipper in order to have one for a backup. If your equipment is paid for, it's not really hurting anything for it to wait in the wing sometimes. I'd rather be able to breakdown and swap equipment and make chips while the sun shines, than be down on a nice day, only to fix it in time for the rain to shut me out. I would love to have a grinder and whatnot, but I can’t afford to give up this advantage. I don't have alot of stump grinding anyway, I’d rather have a loader first.
I'm also looking at having some more part-time help this year, including a climber. If I have to split forces for any reason, I have the flexibility to do so. It gives me a little room to grow too.
The only extra costs for me are plates and insurance, but the pros still far outweigh the cons in this scenario. And I suppose, overall, that whether the equipment is in use or not, each job is billed to cover what is required to accomplish the task and each piece of equipment will give and take accordingly.
The only time that I would go a great deal higher than my average would be when employing more specialized equipment and techniques. I have a local hackmaster low balling me with an old crane, and I laughed when I found out. I'm sure it's quite a bit faster, but, me personally, my rates would be somewhat higher per hour for that. And thus, if he did raise them, he still might be able to beat my removal time and price, but not by as much as he is now. It will catch him eventually.
I win some, and lose some with my basic rates. As a result, oddly enough, I usually get those I want to work for, and can't get the ones I don't want to work for.
BTW, there are some great threads on bidding that you might search on this site if this thread doesn't take off.