How accurate are the SNR AGC readings on these enigma boxes. (Both running latest Vix)

My readings on Cable are

SNR 55% -AGC 0% - BER 0% on my New ET8000.

If I plug my VU + Duo 2 in to the same cable I get a readings of SNR 98% - AGC 99% - AND BER 0%

I had no other cable connections at the time I carried this out.

Can anyone enlighten me on whether there could be a problem with the ET8000 tuner.

The picture quality on the VU+ Duo2 is better than the ET8000.

Thanks