I have yet to take a look, but can you mock up your expected/desired results to make the request a bit clearer? Folks are a bit more inclined to jump in if they can verify the results that you're after -- a visual mockup or description of what you'd like to see on the resulting viz would be helpful, I think. Best wishes!
You are providing 2 dates - are you looking for a month over month growth rate based on the start date month v end date month or oar you looking for the periond vs prior year?
What I would like to achieve is to provide the status of a product or a Client if the monthly growth rate (based on sale and/or orders) has hit a certain percentage. The percentage use to calculate the status is based on an input value, using a parameter. Below is a sample calculation
A) winner = if growth rate is more than x%
B) loser = if growth rate is less than x%
C) steady = if growth rate is below x%
D) dead = if there’s no order for the past x months. The number of months is based on an input value too, using a parameter.
The growth rate is calculated based on a given period of time (start date and end date) i.e.
growth rate = (end date / start date)1/n - 1 < where n is number of months