Understanding influx_inspect report output

We’re looking for some basic explanation about influx_inspect report output. Specifically, it’s not really clear what the ‘Series’ and ‘New (est)’ columns of the report output represent per-shard.
Are these the estimations of how many series are there per shard? if so - what’s the difference between the 2 values?
How do these values correlate with the output of SHOW SERIES CARDINALTIY? From our experience the report shows much higher number then ‘show series cardinality’.