It cannot be pinged if it is off, if it is a newer phone with GPS it can be found, as long is it not damaged. In order to ping a phone it has to have a signal sent to the phone from the tower. It was stated MS had an older phone. I estimate it to be the type of phone my son has since they are nearly the same age. I would not be able to send a ping from the tower for his phone if it was off, nor would it have gps because it is a basic slider phone just like hers.
Bear in mind I have not been in telcom since Verizon eliminated my job in 2001, however I was in telecom for 12 years. Things have changed a bit b/c of the popularity of smart phones, but the basic premise is still the same.
I tend to believe that the 3:30 time frame is consistent when Verizon lost "touch" with the phone.
LA