Sales Analysis Report - part total QTY

How can I easily add a ‘part total - qty’ field? The report summarized ext_price but not qty shipped field anymore? Why would they take that out? I’m sure MANY users use this information.

The expression for the total price summary (by part #) field is:
=FormatNumber(RunningValue(Fields!Calc_ExtPrice.Value,Sum,“sortByLine”),First(Fields!DecimalsPrice.Value, “Currency”))

I thought I could just copy that and modify as follows:
=FormatNumber(RunningValue(Fields!SellingShipQty.Value,Sum,“sortByLine”),#,###)

but I receive an error:
The Value expression for the textrun ‘txtCalc_ExtPrice3.Paragraphs[0].TextRuns[0]’ has an incorrect number of parameters for the function ‘RunningValue’.

What am I doing wrong?

Anyone else EASILY add a summary field for the qty shipped? OLD verisons included this in the base report

Not sure what this section does - since it is a qty field - I don’t need decimal places

,First(Fields!DecimalsPrice.Value, “Currency”))