Difference Between Karma & Karma Coins

Hello! Can someone please point me to information regarding the difference between Karma and the Karma coins? I have several team members that see to different numbers; Karma is generally a higher number than the Karma coins allotted to them for reward redemption. They, as am I are under the impression that any Karma given out should be available for them to use in redemption. Some examples of a difference in numbers: 400 Karma, 99 Karma Coins; 325 Karma, 83 Karma Coins. I would like for my team to be able to use all of the Karma they have received to redeem for rewards. Thank you, again, for the help!