Just to clear things up for everyone else:
at the present moment, the “correct” value for Packet rate is about 10.3, Bitrate is about 20200, and Audio bitrate is about 8100. If you see your reported values significantly lower than these you are losing packets. This is true even if the Packet Error Rate value is low/zero.
Packet Error Rate (or equivalentlym the Valid packets %) reports packets that were received by the radio, but failed integrity checks. It does NOT include packets which were not received by the radio at all.
For example, in the screenshot posted by @kenbarbi, his Tuner reports 8% packet error rate. But the reported packet rate is 8.57 which is about 20% lower than the nominal value. So whats happening is that his radio is entirely missing about 12% packets and then additionally 8% packets are failing integrity verification.
So its important to match the packet rate against expected value, just looking at the PER or Valid % is not enough.