I've read that some Access devices would have data that did not match the display. I know you don't have an Access but maybe this is related. Maybe someone else will have some idea.
One last thing you can try though is to create a new WU station ID as maybe it's a WU issue. You don't have to delete the current ID. Just create a new ID for testing. Then go out there and manually tip the rain gauge to have it register some rain data for testing. Then you can go back to your original ID and maybe test to see that it does work there too. If not then you'll kown it was a WU issue. I've read of some other people reporting that some WU IDs are messed up and creating a new ID fixed the issue.
