The development version has an option to configure Power button behaviour in Kodi menu (Settings -> System -> Power saving). You probably want to set it to "Suspend" as some boxes have trouble waking up by remote control from "Power off".
Just to confirm that this Particular Box "Powers Off" via remote.
Using the .005 version it "Wakes Up" after power off.
Using Power Menu and choosing Suspend , The box Powers Off not Suspend. (.005)
Using the Development Build I tried the suspend option from my "Power Menu" and it Powered Off.
Doesn't seem to have Suspend.