You are using the wrong technique to solve this. Excel provides a built-in capability that would do this for you in a matter of seconds. What you want to do is create a pivot table. The steps to accomplish this are:
- Select the entire range you want to use to perform the calculation
- Under the Insert ribbon tab, select Pivot Table. This lets you create the pivot table from your range. For convenience sake, choose New Worksheet to create the pivot table based on your data in a clean working area.
- You have a blank pivot table. Drag the Identifier field down into the Rows section.
- Drag the ACCOUNT_VALUE field down into the Values section and ensure it is set to Sum of ACCOUNT_VALUE. If you want to change the name that is displayed, you can use the Value Field Settings to change it to something more meaningful.
Congratulations, you now have a sheet that summarizes the identifiers and gives the total value for them.