If we are charging $100 a week for $20 a week that is $2,000. What I need to see is, if the product takes up 16.99 cubic meters, then how much are we charging per cubic meter?
I assume that you mean you were charging $100 a week for 20 weeks rather than what you actually typed into your question, above.
That means you have been charging $2000 to store a product that takes up 16.99 cubic metres.
So, the charge rate is: $2000 per 16.99 cubic metres.
i.e. Rate = $2000/16.99 per unit cubic metre.
And 2000/16.99 = 117.7163 = 117.72 to 2 dp
Your charge rate then is: $117.72 per cu. metre per 20 week period.
You should note that, since you are storing for a 20 week period, then your charge is not so much per cubic metre, but so much per cubic metre for 20 weeks.
You could change this into a weekly rate as: $5.89 / cu metre / week.