I'm not singling you out 1013. The fact is operating the Dash inefficiently was ingrained in the Dash culture and indeed some of it was SOP.
850 MCL and pitch 5 made it go fast but it wasn't as efficient as it could be. That's the way I was taught to fly it and I'm sure you were taught that way too.
It was never difficult to realise that if you were ahead of schedule and you slowed down a bit you'd save some fuel, even before this new fuel efficiency push.