Okay, thanks for the explanation—your use of the term "SOG" threw me off because we don't have anything called by that term available through the CIQ API (though some products do provide SOG values in data fields). I'll get a ticket created and have this investigated.
I'd like some more information to make sure I understand the issue. We don't have any Connect IQ APIs that offer SOG as a value (for example, Activity.Info will provide average, current, and max speeds, but not or average SOG or average nautical SOG). Is the problem that you aren't seeing something like averageSpeed during GPX playback?