Determining Percentage of Customers by $ Value Paying in X Days

I'm seeking to forecast when a business should receive cash in the working capital cycle. For a year I expect ~$225k in cash from a customer base. But it's unknown which customer will require work/how much work. And each customer takes a different length of time to pay their invoice (some 0 days from receipt and some over 100). I'm building a model to forecast how much cash is required in the working capital account for any day of the year (+/- a margin of error).

How should I build the distribution formula to determine what % of the $225k should be paid in 0 days vs X days, vs Y days, etc.?

Sample dataset attached.

Appreciate any thoughts/help!