1) You can change the differential of each stage up to 3 or 4 degrees (can't remember the actual number). I think the finest diff though is .5c (about 1F)
2) To the best of my knowledge No.
3) Never played with the "commercial" side of the stat, but the manual strongly suggests that you do not play with those settings that you're talking about unless you know exactly what they do.
2) To the best of my knowledge No.
3) Never played with the "commercial" side of the stat, but the manual strongly suggests that you do not play with those settings that you're talking about unless you know exactly what they do.