Will I still hit TrueRange if I switch modes?

The SmartEco mode works best if the entire ride is in SmartEco mode. However, if you switch to a higher mode (say, Sport) and come back to SmartEco, the achievement of TrueRange depends on how long the bike was in Sport, how efficient the ride during SmartEco was etc. The longer the bike is in SmartEco, the higher the chance of getting the TrueRange.