The labels on oil bottles often don't tell the whole story - and legally so in some cases. Cosmetic grade oils are one example as well - they can be cut up to a certain percentage but still labeled as simply one oil. The soap lab calculator is one you've used all along? I'm at a loss as to why you've had these problems now that it seems you did everything correctly. 10% of oil weight is a considerable amount to need to add to reduce the zap (unless you zap tested too early). I hope somebody else comes up with an idea.