The Grand Cherokee 2011-2019 has an interesting roof set up.  Jeep put these 12 threaded buttons (6 per side) on the roof. Nice right.  Well almost.  First of all they used the front and back ones to hold the fancy channels used to take roof bars, then are held down via the 4 in the middle. Biggest problem is they are located on a section the the roof that can't really take much weight at all.  Hence why Jeep gave the roof some crappy load rating. This is because if you put more load up there you're going to damage your roof.  
Then we have some roof rack manufacturers (not Offroad Animal) who mount their roof rack directly onto these buttons.  Tsk Tsk, bad choice.  Say hello damaged roof if you put anymore weight up there (don't forget to add the weight of the roof rack too.)
Offroad Animal is kind enough to offer our Roof rack mounting rails to those wishing to make their own roof rack or upgrade the mounting system from a competitor.  These super slim rails push the load to a strong part of the roof (join of Roof and sides). Not only that but they use the rolled steel rail to join all 6 roof buttons per side for one strong system.  So just like that you can up your roof loading to 120kg.  Nice right.  We think so.  
 
Here is a picture of a damaged roof button from putting to much weight on the factory system.