Since we just pushed out the official 4.7 release, would you be able to test this on a new project with that version?
I am going to attempt to reproduce the issue you are reporting on my end within this version, and will report back here with my findings. If there any specifics about the steps I need to take please let me know.
I was able to reproduce the issue you are reporting on an iPad4. I have entered a bug with the tag UE-11267 into our internal system. I made sure to make a note as well that if these values are not accepted, to clarify that within the Documentation pages.
If you have not had a chance to look at the Documentation page for this particular configuration, have a read over and see if you are overlooking anything as well.
Setting Device Profiles
If you have any further questions or need additional assistance please let us know.