Years ago, Zifer in Italy developed the "universal" mount system that most all roof tents use today. It is a system and we would bring the sport bar manufacturers into the mix. It was developed with Thule in Europe. Here in the states we would work with Yakima, who didn't like the idea of roof tents at all and didn't test their bars with our tents. That left us on our own when we recommended Yakima, so there were certain applications like on Subarus where we would go with Yakima as their system was superior. We didn't recommend Yakima gutter mounts, because the plastic wouldn't take impacts well. Hummer tested them and we did have some that broke. I don't remember it being a safety issue, just a product issue.
That being said, we did our own crash testing independent of AutoHome in Italy. We had a firm in Livonia MI contracted to see how the universal mount system handled impacts. On two 45 mph simulated crashes, the mounts would slide 2 inches, which was a "pass" and the system was certified as OEM by one of the Detroit manufacturers.
Turns out, the controlled slide is very important as it seems to take up a lot of the energy. One of my best friends was rear ended while coming back from a Mexico expedition. He was doing 55 as he was towing a trailer and rear ended by a vehicle doing an estimated 100 mph. Again, the tent and mounts slid 2 inches back and the tent was the only thing that wasn't totaled by the insurance company.
I would bring the roof tent representative into the mix and see how their experience has been with your roof bar system. If you are having trouble with your mounting system on the trail, that doesn't bode well if you are in an accident. Then again, take what I say with a grain of salt as I am going back to the development day of roof tents, things are different and the manufacturer you are upset with didn't exist so I have absolutely no information there.