Why did Blaney and McDowell Switch Rides?

I'd have a true definitive answer if I glanced at the Cup standings, but it's probably for points reasons. If they are on the same team (not quite sure), the owner could probably swap them so that whatever team has the lesser points (let's say McDowell here) uses a more experienced driver (Blaney) to qualify the car, and hopefully get as many points during the race as possible.