For yesterday (8 Apr 2019), OpenSky says I reported 61,136,062 Mode S messages, of which 15,291,778 were Extended Squitter, of which 5,744,721 were Airborne Position and 5,756,120 were Airborne Velocity. That seems to match up with typical message rates and position rates I see in SkyView locally, though I’m just eyeballing that.
However, my FA stats page says I reported only 811,284 positions on the same day–an order of magnitude lower than what OpenSky says. What’s with the discrepancy?
FWIW, the number of aircraft is usually within ~5%, which seems to rule out a lot of likely problems.