This object reports the actual line number where this ancillary service was found in the top field, or full frame for progressive signals, of the SDI signal. This is the ground-truth counterpart to the expected line number, and an admin uses it to confirm the ancillary data is actually landing where downstream equipment expects it, since a mismatch with vancServiceStatusADJLine could explain why some downstream gear reads the service correctly while other gear doesn't. If this object reports line 12 rather than the industry-standard line 9 for AFD, an admin would know some downstream decoders configured to only look at line 9 may fail to detect this service even though this device correctly reports it as present.