I find I need to be pretty near level, like within 1 degree, or the system will actually go a bit overboard and lift the wheels off the ground.
There's also a gotcha where it is possible for it to not be able to lower it enough if the pin/front jacks aren't set right. For example, this last weekend, the system couldn't lower the front end enough to get it level, so it wanted to raise the back end way up to compensate. I don't like the wheels off the ground. So, I put it back on the truck, put 3 of those plastic blocks under the jacks, and that gave it enough play in the up/down so that it could lower the front enough to level it.
I hope that last paragraph made sense.
