Good point.....I am using VWSaprs along with WSWin 2.93.8 to send CWOP data....I could try VPLive and see if this solves it....Unfortunately we probably will not get to zero or lower here after this morning..
I'll save you the trouble.
I'm using VP Live now. Since Steve already visited a problem recently with below zero values I figure if it was something in the software he would have solved it already. Since your using VWSAPRS and seeing it too that convinces me it must be the decoding on CWOP's end.