Untrue, thats because BLM DOES have an Enhancing skill. How else are you able to use Blaze Spikes then? The Healing skill however from a WHM if is not capped, will not rise at all if you are a BLM/WHM. Because Healing magic isnt shared by the two classes, whereas Enhancing does. So Protect can be used to raise your Enhancing as a BLM/WHM because BLM already has an enhancing skill.