DJI Phantom 4 RTK and Pix 4D Georeferencing Error

Thanks Blaz. I followed the provided workflow and still experienced a similar error. (see photo, sorry about the photo quality)

This quality report was generated after entering my GCPs as check shots and re optimizing. If I change the check points to gcps and re optimize the average rms error for Z is 0.404ft.

For comparison, I also flew the site with a standard Phantom 4 pro WITHOUT RTK and using GCPs my average rms error for Z is 0.159ft.

I was hoping the P4RTK would have better results if not much better with out without GCPs. Is there a mistake I could have made in initial processing or camera setup?