Rural sites don't get jammed up let alone in the middle of the night..
Possible, my phone is constantly updating something i'll try it if i have coverage issues tonight. that may cause issues with my secondary trigger, voice mails coming in.
Who knows, I'm pretty sure most of the time I roam off the US Cellular tower I'm working on. ( multiples each night) but, sometimes the signal is too low to be the same tower so there must be some sort of roam priority, can't say any one of them gives me my incoming.