For the devices that seem to limit intervals to 30 or more mins, I wonder if those devices are smart enough to limit *anything* in the app from running less then 30 minutes apart, or does it just limit a particular service from running less then every 30 mins?
Because if it only limits a particular service, then theoretically you could have 6 different services setup to run at different 30 min intervals (separated by 5 mins), and when each of the 6 services are triggered, they could then call some central routine that does the actual work of the app. So in a sense, these 6 services would be just dummy services.
If this is true, then this could mean you could get your app to reliably run every 5 mins even on devices that try to limit each service to no less then 30 mins.