Why is the method for calculation of Burdened Cost different?

Summary:

If multiple costs (direct costs) of the same Task, Expenditure Organization, and Expenditure Type are imported and then execute to Generate Burden Costs, how is the amount of Burden Costs generated calculated?

The following situations are currently occurring in my customer's test environment.

1.Multiple Row Costs are imprted

2.Burden Cost is generate at once.

3.Different calculation logic for the amount of Burden Costs generated

The following screenshot is a table of the corresponding Row and Buden Costs exported from the Manage Project Cost screen.

①->Rounded Statements are summed.

②->Totaling statements rounded.

Why is the calculation method different?