Incentive Compensation

Has anyone ever built a plan using a formula with the target variable comp, component weight and the external metric numeric other amount 1?  I'm trying to build a plan that basically takes 10% of the base salary (target variable comp) x component weight (comprising of a bunch of mainly percent interpolation external metrics) x a funding value with I'm trying to use the external metric numeric other amount 1.  If I don't include the external metric numeric other amount 1 in the build, it works fine.  If I do include it then the payouts just don't calculate.  Thanks in advance for any assistance...