Mobile Edge Computing (MEC) has received much attention from the research community in recent years. A significant part of the published work has studied the telecom-centric MEC architecture, which assumes that the computing resource is located at the edge of the mobile access network (e.g., the Evolved Packet Core or ePC), typically at the first aggregation level. Many of these studies make a silent assumption that the latency at this stage of the network is negligible. We show not only that this assumption is false, but that in some common cases the latency of the first aggregation stage dominates the end-to-end latency. We further show that common probing metrics can easily fail when used to select the service site for an application and discuss possible improvements to server-selection reliability.