How to create a modified stacked bar chart for service consumption data, with roll-over?

I am trying to create a visual representation of Service Hours for a customer.

A customer contracts with us for 1+ years. When they purchase a service package, they buy a number of hours that they can "spend" to work with our Professional Services, Solutions Architecture, etc teams. Those hours are allocated annually and unused hours roll over until the contract expires.

Example:
Customer under a 3 year contract purchases 180 hours, 60 hours per year. Last year they billed 43 of 60 hours, rolling over 17. This year they have billed 37 hours, consuming the 17 roll-over hours and 20 hours from the current year. 30 hours have been scoped for outstanding projects this year and 30 hours have been scoped for projects planned for next year.

Workbook attached.

This is what I want the end result to look like.
IMG_0131 Large.jpeg

The simplest descriptor of what I'm trying to accomplish is a stacked waterfall chart. Part stacked bar (X of Y hours consumed) and part waterfall (Year 1, 2, 3 etc as components of the total purchase).

I haven't been able to accomplish this via stacked bar charts, even deleting/hiding bars, but its possible that I might need to restructure my data and it would work that way. I'm hoping this forum can provide some guidance, so thank you in advance.

You got me on the right track. Based on what you did, I was able to create an output that generated what I wanted.
Attachment 887527

The last thing I need to do is ensure the formulas are dynamic and able to adapt to contracts of different length, as well as variable purchased/consumed/allocated/rolled-over hours. Here are my formula sets and I think I've edited them appropriately, but could use a proofread. Specifically the part that I'm unable to account for is the formula change from "current year" (2) to "future year" (3) in column T.
Attachment 887529

Updated workbook uploaded.