We don’t have Smart Manager on our phones. A quick google says AT&T removes it. YAY … thanks for taking away something that might have been useful to make room for bloatware that I immediately disabled! Sigh.
Regardless, power management should affect both my phone and my wife’s phone equally. Yet my presence is detected reliably (as much as I’ve paid attention to it), and my wife’s is not. On the other hand, I shut down tasks regularly and reboot occasionally, and my wife doesn’t pay attention to those things. So there could be other factors.
@R2D2, I’ve come across several threads on this topic since I started reading the forums last summer, and the consensus as I recall is similar to what @rdelavega said … presence is more reliable on iPhone than Android, and dedicated sensors are more reliable than iPhones, and none of them are perfect.