Could you describe your process for optimizing the mixture on the ground? It also sounds like this is the mixture setting you use for takeoff.I live at an elevation of 4,000' with DA's commonly at 8K or above in the Summer. We practically never ever use full-rich mixture. That stuff is for sea level dwellers. We taxi at just above ICO to avoid lead fouling. We optimize mixture at run-up and this usually results in a knuckle or more pull on the mixture knob.
Once you get fairly familiar with a specific aircraft you get very good at approximating the mixture setting for landing based on experience and seasonal temperature changes. Both prior to run-up and during descent to land.
I’m at a field elevation of 4000’+ …