This can be done using Tableau as well:
sum( zn([%]) + 1 ) * PREVIOUS_VALUE( [Initial] )
I've attached the workbook also, so you can see what happens, but this is how it is supposed to work:
First zn() around percentage ensures that there is always a percentage (your first value is NULL, so zn will replace it with 0).
Then add 1 to it and sum it because it needs to be an aggregate (however it is the sum of one row, so it is the value of the row).
Then time previous value - which returns the value of the same calculation in the previous row OR - if it is the first row - the value between the brackets. I've made that one a parameter called initial, which is set to 10 according to your description).
Note that this is a table calculation, so needs to be set to run along table (down).
Hope this helps!
Previous_Value.zip 13.4 KB
This is great. Thanks so much Dana