What about why the S4 had low standby but the N5 has high standby. Do you know of a reason it would be different for those two phones?
Not sure why, but there some differences. The Verizon note 5 supports pcs lte, the Verizon s4 doesn't. Also, the s4 had 2 cellular paths. The Note 5 had only one. The s4 had the baseband chip integrated into the soc, both being qualcomm. The Note 5 has a Exynos cpu with a discrete baseband processor.
It could also be something else. The Note 5 and s6e are very similar and the note 5 has 15% larger battery. Yet in my usage, the note 5 gets 50% better battery life, if not more.
Disabling volte and changing the mode to lte/cdma are the only things that I can think of, without root.
Sent from my Verizon Samsung Galaxy Note 5