There are two path types used in Delivery monitoring: single-ended and dual-ended.
A single-ended path is one that is monitored in only one direction: source to target. Single-ended monitoring involves sending a train of ICMP echo requests to the path target and measuring various aspects of the packets received in response. Network devices and end-stations generally respond to ICMP echo requests, so a monitoring point is not required at the far end.
A dual-ended path is one that is monitored independently in both directions. For this, the path requires AppNeta monitoring points as both the source and the target. Monitoring in both directions is required especially for paths that have asymmetric loads, like video conferencing and user-site Internet connections. Dual-ended monitoring uses UDP. UDP isn’t purpose-built for discovering and announcing network presence like ICMP, so an AppNeta monitoring point is required as a target to respond to UDP probes and to initiate diagnostics tests in the reverse direction.
Because these two path types use different protocols, and these protocols may be treated differently in your network, it is possible that their respective performance metrics do not match.