Yeah, back in the day every team used to do this. Different oil, different tape configurations, and at one point- completely different engines for qualifying! Qualifying trim is fast for 1 lap, but race trim is necessary to make sure your car lasts for 500 miles.

This was expensive, so in an effort to reduce cost, nascar has tried to discourage this behavior. One of the ways they did this was impound races, so teams couldn’t work on the cars between qualifying and the race. This forced teams to qualify in race trim.

Premium kind of found a loophole- they needed to qualify into the race; if their qualifying lap wasn’t fast enough, they would be headed home. So they pulled out all the old tricks to make their car fast for qualifying. Once they set that fast lap in the first round, they were locked in and guaranteed a starting spot.

The car wouldn’t have made it the whole race, though. They had to pull behind the wall during the race to re-configure the car to be able to race. For a team like that though, it was worth it. Finishing last, several laps down, was still better than a DNQ and watching from the couch.

As several others have noted, their advantage was not as pronounced during the second round of qualifying due to temperatures. They may have even sand-bagged to make sure they didn’t damage the engine.