As drees said, driving style could make a big difference. If your wife was following you, then she may have been on and off the throttle more to try to maintain the proper distance.
Another issue can be that the cell balancing can make a very big difference in range. The newer LEAFs (MY2013+) are reportedly better in this regard, but who knows?
Also, there have been several LEAFs out there with ~90% SOH when new which still would travel just as far on a range test as other cars with a SOH of 100%. However, doing that required driving quite a few of the miles below LBW and VLBW. Read this thread
for more details.
Finally, the battery temperatures would have been quite different in your test. The demo LEAF you purchased may have been charged some time ago and cooled off while the battery in your old LEAF would have been warm when you arrived and would have warmed further as you charged on the ChaDeMo.