The "true altitude" aka AGL is pretty useless in digital. Easiest to land with an analog readout like is included in the "Steam Guages" addon. I just don't want that addon running as well. It's slowing my game down.

The thing is, this is a mod for autopilot and raw data. Guages take art assets, extra coding to make an overlay, making sure the gauge works correctly and settles at the right spot, etc.

Also, why re-invent the wheel? Maybe ask the original author of this gauge mod to check into performance issues.