SCIO was initially fought to be single equation or table but it had to be split into clinical and growth parts, as their key factors should be evaluated separately rather then simply added to each other.
Clinical and growth components provide tools for the clinician to decide, whether to treat systemically and if treat, than for how long. The stratification for needs of comparative studies requires complex evaluation of factors. For that purpose we propose general (common) equation, the modified multiplication of growth and clinical components. The possibility for multiplication of severity (i.e., form and hyperkeratosis) by extent (i.e., depth) and growth-rate is obvious, as those factors independently impact the outgrowth of the affected part of the nail.

As in clinical component, final SCIO equation has tricky extra calculations to avoid evaluation of growth component in SWO where it is irrelevant. To reduce big numbers, all is additionaly divided by 3.