want to calc difference between 1st N numbers that appear and 2nd n numbers that appear for a data table

[Lady_miche]

I have data Arranged as Below what I am looking for is an Array formulae maybe that would calculate the difference between the average of the 1st 2 times a number appears on the row & the average between the next 2 times a Number appears within a fixed range.



Below is an excerpt from a Rate of sale tracker and I want to look at the Rate of sale decrease between the 1st 2 weeks a Product is Live vs the 2nd 2 weeks a product is live for. However I can only find offset formulas which starts counting from the start of the range as oppose to the first value.



I would like to return the Values the Column GD

 

[Lady_miche]

I have data Arranged as Below what I am looking for is an Array formulae maybe that would calculate the difference between the average of the 1st 2 times a number appears on the row & the average between the next 2 times a Number appears within a fixed range.



Below is an excerpt from a Rate of sale tracker and I want to look at the Rate of sale decrease between the 1st 2 weeks a Product is Live vs the 2nd 2 weeks a product is live for. However I can only find offset formulas which starts counting from the start of the range as oppose to the first value.



I would like to return the Values the Column GD