MCP is short for Mode Control Panel. I think that’s not technically the correct term for Garmin units (it comes from Boeing flight decks) but I’m referring to the panel in the top middle with the auto pilot selections and knobs. The Altitude knob for the G3000 and G5000 toggles between 100 and 1000 feet increments when pushed in. In FS, that involves clicking the middle of the knob.