Calculated Column not being displayed in visual correctly?

Here you go. I had to make a number of changes.

1. Created a date table and related it to your data table.
2. Created a date in your data table. "January" won't work. Made it Jan 1, 2020 for example.
3. Created measures for Total Employee Count, Total Amount Overdue, Average Overdue, and maybe 1-2 others.
4. Redid your chart.

You cannot bring in averages and percentages in your source data and do anything with it. You have to do all of that with measures or it won't roll up right.

As a rule, you NEVER want to drop numeric columns in the VALUES area of a chart or visual. You only want to drop Measures there. The reason is when you drop a value, Power BI creates an implict measure, and you cannot control it as well as you can an explicit (user created) measure, and you may not understand weird results as your model changes, as Power BI is doing what it thinks is best, not necessarily what you want.