Add Incremental Data to my Chart

A day late but here it is.

I converted the data into an Excel table. I did this because tables know how big they are so that formulas, pivot tables and charts build from them do not have to be modified when data is added to or deleted from the table. Also formulas are expressed in terms of column headers which make them easier to understand and debug. (This also works in VB code). Keep everything in one table. If you want month view, you can filter the table.

The tally sheet has, as you noted, date range formulas for tasks raised. I added some helper columns to keep the program "flexible." I could have hard coded these values into the formulas. The spreadsheet is almost ready to roll over into the next year if the project lasts that long. It will take a bit of modification, but not much.

The formulas are COUNTIFS.
=COUNTIFS(Table_Master[Date],">="&[@Start],Table_Master[Date],"<="&[@End]) - gets the tasks raised during a month.
=COUNTIFS(Table_Master[Completed],">="&[@Start],Table_Master[Completed],"<="&[@End]) - gets the tasks completed during a month.

As for the chart: I made this dynamic. So as you start adding months to the chart, the chart will grow.
The details are in these links:
http://www.utteraccess.com/wiki/Offs...Dynamic_Ranges
http://www.utteraccess.com/wiki/Dynamic_Charting

Specifically I created a range: Plot_Month =OFFSET('Tally 2019'!$A$4,0,0,MATCH('Tally 2019'!$F$1,Table_Tally[Month],0),1) - this range is defined as
- Start in cell A4
- Go down zero rows
- Go right zero columns
- give me a range MATCH($F$1,Table_Tally[Month],0) rows deep and 1 column wide.

Since today is in March, F1 = "March" and this formula points to the range A4:A6. In a couple of days, it will point to A4:A7 and the chart will pick up April.

I defined two other ranges
Plot_Raised =OFFSET(Plot_Month,0,1)
Plot_Closed =OFFSET(Plot_Month,0,2)

These are exactly the same range as Plot_Month but offset to the right by 1 and 2 columns respectively.