The Kolbach index is the degree of modification. You can have different DP for malts with the same Kolbach index. Some malt varieties have high DP (6-row, NA 2-row), others are lower (British varieties). Degree of kilning can reduce the DP of the malt, so pils>pale ale>Vienna>Munich.
I couldn't find the WK for Weyermann's malts on their spec sheets online. I'm away from home, so someone else may have them somewhere. You could email Weyermann and ask.