It may be wording. It may give six into the spell. The staff which is supposed to give mana back for using a spell doesn’t give yellow mana for example but instead gives mana back into the spell that was cast only. In the same sense each different colored spellay get the 6 mana without that stacking. And stacking would have been my assumption, so 4 colors give 24 to each, but they seem to have worked on starting mana quite thoroughly, I don’t see any gear that is actually still useful to starting mana.