Try waiting a little longer next time. It may not help, but then again you may be manually turning off the ICE only a few seconds before the controller in the car would have done so. Frankly, I find the algorithm that controls the various drive modes to be mysterious. It engages direct drive when I wouldn't have predicted, and then abandons it when it seems most reasonable. Same with turning off the ICE at odd times. Then again I'm the kind of guy who would be driving a manual transmission if that were an option.