m0useanswered grow question 3 years ago I would be inclined to do what the manufacture says for its light heights unless you have a light meter.
The height of a light vs the seedling or canopy is all based on how strong the light is.
Not every light is the same strength. Light is measured in a few forms as PPFD, PAR, or DLI and others, its all dependant on that measurement.
https://www.growyour420.com/ppf-ppfd-dli-par-values/
watch the video at the end of it. it does a great job explaining everything about light that can be cramped into 16min.
Good Luck