Crossing the threshold a half dot, or a dot, is a relatively small displacement. IMO a bigger issue is demanding "don't do this, don't do this" so guys make relatively large changes in aimpoint/touchdown point because of an over concern about being slightly low.
At 100' a half dot is roughly 2.5 feet. A dot is five feet(+/-). If your aimpoint/flight path is correct you'll cross the threshold 1-2' from ideal. That's not the end of the world. Making a significant correction and losing your aimpoint/flight path, and perhaps requiring a secondary correction, puts you at risk of a bigger deviation from acceptable performance.