Ok, so re-setting the trip odometer works for figuring out average mpg at present. If you let the trip counter run for too long, the computer aggregates too much data and inevitably average mpg will be right around 19-20 if your driving is a combination of city and highway. As Synolimit suggested, I reset the trip counter on the highway and it showed 32 mpg at 2500 rpm in fifth gear. Problem solved.
Reverse continues to be an issue, though, but it has gotten better now that break-in is done and over. But the problem is not gone, and it can happen on a flat road, full stop, with the engine warm. My first service is at 3000 miles, so I will definitely bring this up then.
Be safe and happy holidays.