Those charts assume you had a long veg and well developed plant and root system. Move it futher away for smaller less developed shorter vegged plants.
Too close and leaves over heat, move it till they feel cool to the touch. It is misleading but read your plant, leaves like to be at 21°c, if they feel warm they are getting too much light.
This can be seen with seedlings, at the chart reccomendations they will burn to a crisp as not enough water can be supplied to bring the leaf to optimun temperature.
Ive found this many times, increase light slowly as plants grow, find the distance at which they grow best.
I cannot use those charts with my short veg time, at this plint i find the distance at which the lumens suit the age and let the plant groemw upwatds as it ages and requires more light.
Light meters can help somewhat but you can tell when leaves are getting too much light as they wilt in the dark cycle and before lights out, tips curl and leaves gain a shiny coating of wax.
Play about, youll find your distance, ignore the charts i grow better for not exceeding the leafs light satuation point.
The seasons work like this too, from winter to spring and finally summer you have a steady increase of light. If your veg plants hate the hps work out roughly the lumens at the top of the plant and place them at that required distance so the hps gives the same.
Shit charts really...
