No they don't test at idle only, they rev the hell out of the little diesels. As long as the
13BT doesnt smoke too much, you will have no problems passing. My old 3B was always really low, almost zero when on biodiesel though.
I wouldn't frete about it.
I've had my BJ60 since BEFORE AirCare was dreamed up by the idiots in Victoria. It has NEVER even been close to 1/2 of maximum no matter how they've tested it over the years from idle, constant speed, imitiation drive etc. etc.
Ya 3b guys could always turn down there fuel settings too. I imagine anyone of the diesels could do this. If you were a smoking truck. But if you don't have a pyro I would pay very close attention to how much you turned it. So when you go back to previous setting you don't over do it.
The ONLY AirCare issue I've had with the diesel is my old '84 I had before I replaced the engine. It had so much bypass that sometimes it looked like a fire was starting under the hood! They wouldn't let it in the station till it smoked less. Fortunately it had it's good and bad days so I just waited for a good day and it passed!