Thinking of doing a same day turnaround to/from NRT from EWR. I know that CO 9 arrives at 1:55PM and the same day CO 8 departs later that afternoon at 4:35PM.

Anybody done this before and had any problems? (i.e. no idea how NRT works...can one stay in the sterile area for a tranist like this or do I need to go in/out of NRT immigration...how likely will they give me an issue with this)

Also, appears that CO 7 from IAH seems to always turn into the CO 8 to EWR...would it be safer to do that? (arrives at 2:20pm into NRT and then turns into the CO 8 at 4:35pm). Also means more EQM's which is the whole point at the same price.

Thanks!