I've always been skeptical of the fluxing myself.
I've suspected the flux material is sort of like the stone in stone soup. Put a stone in some boiling water, add some meat, salt, and vegetables and voila' you've got a great soup!
Likewise, add your flux, stir the melt, and voila' the melt is now well mixed.
But I still add some wax anyway - just in case. :roll: