Could you give an example?
I start with the base image
I make a mask per the tutorial
I perform the tutorial steps, sometimes having to fiddle with the size of the median and gaussian blurs and end up with a gloss map
I put the gloss map layer above the base image layer, set the gloss map to OVERLAY and adjust the opacity to my liking, to get something like
This works well for metal, plastic, cloth, anything that might have some shine, reflections or sheen to it.
You can edit the gloss map if it puts highlights that are inconsistent with lighting, etc.