Ok, so have had my P4 for little over 3 weeks now. From the start I always had a slight tilt of the camera to the right. Using the Gimbal Roll setting, I clicked up about a plus 3 to get the horizon straight. After a week of use I used my reliable setup I made for my P2V+ bird. It's a piece of 5/16 lexan with 4 threaded bolts to allow for adjustments. I used the bubble ;eve; app on my phone to ensure the plate was level. Did the IMU calibration, then the gimbal calibration. I had reset the gimbal roll back to 0 before doing so. Took it up aftewards and still had the tilted horizon. I did that a couple more times but each time I would have the tilted horizon and have to correct the roll in the settings. Today I double checked the level of the plate with a real bubble level Come to find out the plate wasn't level. Never was. Recalibrated both the IMU and gimbal. Lo and behold, after taking it up to 100' and horizon was right on the spot. Did several pans of the quad and it was dead level steady. Whoop!