This graph is rather interesting.


Although the curves are approximately linear, the slope of the curve is quite flat. Using the upper curve, the wear at 1% soot is .0039. The wear at 2% soot is .0044. This represents a 13% increase in wear for a doubling of soot. That's a decent tradeoff, IMHO, and it suggests that running 2% soot as a maximum is hardly detrimental as compared to the traditional 1% limit.

Based upon this data, I'll seriously consider raising my OCI above the current 5K.