The KSum/KAvg Options dialog (accessed with the Details [...] button to the right of the KAvg toggle in the sidebar) allow you to choose the averaging method and also to optionally specify a weighting variable.
Averaging Methods
The following averaging methods are available. The current averaging method appears in the plot title.
• Arithmetic Average: 
• Geometric Average: 
• Harmonic Average: 
Weighting Methods
You may choose a weighting variable to be applied to the grid variable at each cell before being incorporated into the sum or average.
For KSum, the value of the weighting variable W is simply multiplied by the grid variable V before being added to the sum, i.e., KSum(VW), the sum of V times W over active K layers for each active I, J.
For KAvg, the method of weighting varies depending on the type of averaging being used, as follows. For geometric and harmonic averages, where V is zero or less, a very small number (specifically, 0.000005) is substituted.
• Arithmetic Average: 
• Geometric Average: 
• Harmonic Average: 
Tecplot RS calculates K Averaging and Summing over all visible K cells. You can restrict the K range using any of the following methods:
• Value Blanking - refer to Section 18 - 3 “Cell Value Blanking”.
• Pick Blanking - refer to Section 18 - 4 “Pick Blanking”.
• Inside Views:
• IJK Slices - refer to Section 14 - 3.1 “IJK Slice”.
• IJK Blanking - refer to Section 14 - 3.4 “IJK Blank”.
• Well Blanking - refer to Section 14 - 3.5 “Well Blank”.