Cumulative Expected Billings to Calculate Future Bonding Obligations

When we invoice a client, it reduces our outstanding bond obligation and increases our bond availability. We project invoices for several months (by day) and always know our current outstanding bond amount. I would like a graph/chart that displays our bond obligation into the future based on our invoicing forecast, by day or week, or by date select. This would be easy to do in Excel (see attached), but ideally, I'd like to do it in QBase. Basically, it is [Bond Obligation] – (cumulative) [Expected Billings] at any given date. The problem, of course, is getting the cumulative Expected Billings "at any given date." Can anything be done in QBase?  Alternately, could it be done in MS Power BI, and how difficult would it be? Thanks in advance for any feedback.