My understanding from the OP website is that this is ineffective for certain popular phone vendors' customizations. In particular, the Nokia phone listed comes

My understanding from the OP website is that this is ineffective for certain popular phone vendors' customizations. In particular, the Nokia phone listed comes preinstalled with an app that aggressively shuts down any running process, whitelisted or not, if the screen has been off for 20 minutes. There's simply no way to stop this behavior apart from gaining root and uninstalling the battery "saving" app, or flashing a stock Android image that doesn't contain it.