I read in the manual that :

# Listeners for Today
Provides a graph of the total number listeners connections established during each hour throughout the current day.

# Listeners for Yesterday
Provides a graph of the total number listeners connections established during each hour throughout the previous day.

I have a client on an Icecast server who has been complaining about inaccuracies in their statistics for 'Listeners for Today' and 'Listeners for Yesterday' . Ive checked this out today and noticed that he is right. He has had at least 5 or 6 constant listeners yet when i manually update the stats to check the graphs they only show a maximum of 4 listeners for that period. Bearing in mind the manual states 'total number listeners connections established during each hour' it should be at least 6 if not more.

Shoutcast servers seem to be reporting the statistics fine. I wonder if this is an icecast specific issue ? Or am i interpreting the statistics wrong ?

Please open a helpdesk ticket.  We'd need to see the logs for the relevant time period and the corresponding statistics in your Centova Cast web interface in order to diagnose this.