Excel math/formula question

Hi,

I'm trying to model out the customer revenue stream for a business based on certain assumptions and was wondering if someone could help me with the same. I need to model out how much revenue the business will make (month-to-month) for a 7-year period given some assumptions around customer growth/churn and the business's subscription model. I've create a preliminary file but wanted to double check and would appreciate if someone could help me with a quick analysis of the same.

Assumptions are as follows:
Billing and Usage
* Customers pay for unlimited storage in advance as follows: $5/month, $50/year (one payment every 12 months, on their annual anniversary of becoming a new customer) and $95/2-years (one payment every 24 months).
* Signups are distributed amongst the 3 payment plans as follows: 70% monthly, 20% yearly and 10% 2-yearly
* Renewing customers churn at an annualized rate of 10%/year

Growth Rates
* Start with 10,000 customers (assume same distribution as new signups), storing 1 TB each.
* Add new customers at a rate of 2,000 customers/month.

We need something to work with (excel template)

This is the excel template/calculation that I came up with. Can you let me know if it makes sense?