Calculations based on summed values in a worksheet

[Sloader]

I am working with a schedule of development parcels. 

I have database rows that add up some calculations based on (summarized by) parcel numbers in a database record, each parcel is made up of sections with different densities, the densities are specified in the database record. 

Summing up for the area works fine and calculating the total units works fine as its the sum of area*density for each section of the parcel. 

The issue I am having is in trying to calculate the resulting density for each parcel. If I sum up units/density I obviously get numbers that make no sense, if I have 2 sections of a parcel at a density of 30 the overall density isn't 60. 

Essentially I want perform calculations on the summed values in the other rows not make calculations for each part then add them up. 

[Pat Stanford]

Unfortunately, that is how VW Worksheets work. Each subrow is calculated individually even is SUMmarized.

 

I believe I overcame a problem like this for someone else with a Worksheet Script to do the calculation.

 

The actual result should be the weighted average of the individual densities. Is that right?

 

DM me a sample file showing what you are working with and I will see if I can come up with an easy solution.