A pay-per-use business model relies on an accurate, or at least, un-tampered, time reference for the administration of prepaid usage time, e.g. hours, or subscription expiration dates. A protocol for provisioning usage requires that any electronic device request for provisioning includes current time at the device. A server responding to the request may evaluate the time at the device and send an updated time when the current time at the device is outside a variance limit. If the electronic device repeatedly sends requests with inaccurate time, the server may cease sending time updates and block the electronic device from further updates for suspected tampering.