...in addition. Many use distance and there is nothing wrong with that. Some believe we should adjust our lights to what the plant sees.I don't know that light, but pretty much all the half decent manufacturers have recommendations. Checking the pdf manual for that light they recommend
1. Seedlings and Clones - 36” - 40” - VEG switch only
2. Early Vegetative Growth - 24” - VEG switch only
3. Late Vegetative Growth - 24” - VEG and BLOOM switches together
4. Flowering - 18” - VEG and BLOOM switches together
https://platinumgrowlights.com/wp-content/uploads/2017/08/Platinum-LED-Grow-Light-Guide.pdf is a direct link to the manual