This indicates whether the far-end current 15-minute bucket's counters are trustworthy, mirroring the near-end ValidFlag but for statistics reported back to this box by the remote SONET terminal via FEBE/RDI overhead bits. Because the far-end numbers depend on the remote device successfully reporting its status through the path overhead, this flag matters even more than the near-end one -- a remote reboot, a far-end protection switch, or a loss of overhead signaling can make this bucket notValid even when the near-end path itself looks fine. If the far-end SONET terminal is power-cycled at 9:03am, the far-end current bucket spanning that moment would read notValid(1) even though the near-end current bucket for the same period stays valid.