What is the point of the "false" version of your stat?

[randale]

For example, my tailoring base is 56.2, and my one which I think it's accurate is 65.2. Last night I was trying to make fancy dresses when my skill was 50.0 base and noticed I never failed. I went to stratics and put in my base skill and I didn't have a 100% chance to make one, but with my non-real stat I did. I'm wondering which one I should use on that or any other skill chart. I have almost a 100% chance to make a cloak with my non-base stat, so I'm wondering if I should make something I have a lesser chance of making with the non-base stat as well.

[iamreallysquall]

the higher value is what being used to calculate your chance it will decrease as you gain skill. id go with the higher value for stuff like magery / crafting