I would question this, particularily with resoect to running with a factory compass calibration.No, it's not! I've only had problems when doing an IMU calibration. From what I understand it's already calibrated from the factory and you don't need to do it unless it tells you. Just like the compass.
Unless your flying within a reasonable distance of the DJI assembly plant in China I would be doing a fresh calibration out of the box.
As to the IMU you nwould want to hope the shipping companies and storeman didnt subject the phantom to any rough treatment. It isnt that difficulty to put the accelerometer out of whack.
For the effort required and potential outcome of skipping the calibrations i would do both.