Losing wanted level optional in heist finaale?

[Nutduster]

My crew is trying to beat the aggressive approach elite challenge right now. We've beaten the others repeatedly and this is the last one left.  On our last run, we bought the decoy driver and tried going straight to the buyer; this has worked pretty well for us at times, but not this time, as the cops in the desert were persistent. We ended up near the buyers, knowing we were over time and still running from the law. So for a quick laugh we decided to go throw grenades at the buyers' SUV, to see what would happen.

 

We did manage to throw the grenades, but as we got near them, it triggered the closing cut scene and boom, heist completed. Was NOT expecting that. We definitely never lost our stars (had four of them after the decoy), and the cops were all around the area.

 

Is this a known thing? Do you not actually have to lose your stars to finish? If so, this might radically change our approach to this elite challenge.