Thanks for the fast response Rick, but as mentioned in the first post millis() and software timers dont carryover during sleep. At least as far as i know, (I don’t have any electrons to verify right now).
I have a regular interval pulse coming in on the WKP pin roughly every 1400ms but this can vary up to 500ms.
Right now I keep a running average of time between pulses and wait for an out of range event (+1/2 duration average) before triggering an alarm. So everything works as it should right now but I want to reduce power with sleep.