https://community.weatherflow.com is the right place for this one probably.
You will need to compare your UDP totals with what WeatherFlow displays via their REST or Websockets interfaces. Make sure you have RainCheck (or whatever they call it now) disabled so that their servers report the same thing as what your UDP messages indicate. The totals should match.
How to do this comparison is something other folks have asked on the WeatherFlow forums and it can be a little complicated, but if you ask 'there' you will certainly get some answers for how to do this.