Add me to the list that have raised their rear jacks. No calibration needed. Be sure to get torque them to Lippert's specs (I don't recall what that is but its on their web site). And I always put at least one extra block under each. I figure a shorter extension makes the RV a little more stable
I also added bolts to the 4 rear leveling jacks. Didn't like that the factory had them two at the bottom and two at the center, so added two more at the top of each. Overkill but the RV was new to me at the time and I was looking for things to do to it