I'm thinking about getting a soulstone but I'm not sure I understand how it works. The way I read the description I can store a skill on it and then put it back on my toon later. But I can only put it back if I have the skill points available. So lets say I decide to learn to cook a little and put my 120 points of swordsmanship on a stone. I then train up 50 points of cooking. After I cook up some grub and decide I want the swords points back, how can I get them back since I don't have 120 points available? Is 1 soulstone by itself useless?