Is it moving in the wind at all? I know that can cause false readings.
The issue I see is that it reports astronomical rain rates but no actual rain accumulation. That messes up Weather Underground bigtime.
So, for background, this is with the usb console hooked up to a meteobridge router. I went this route to try and get around the random reset of the raindfall accumulation during the day that I was experiencing on the Acurite internet bridge.
The author of MeteoBridge looked at my data and said it looks like the USB console is reporting whacky data. I don't get the feeling that Meteobridge really supports ACurite amazingly well though.
The unit is mounted on a galvanized pole attached to my house, and there is almost never wind.