I'm not sure that you understood the core problem of circular referencing
which I identified/mentioned in my earlier response.

Anyway you could try the below, which should resolve the circular
referencing bit, and possibly return exactly what you're seeking to do

In sheet: SUM,
Put instead in B2:
=IF(B$1='Source data'!$B$7,INDEX('Source data'!$C$6:$E$6,ROWS($1:1)),"")
Copy B2 across/down to H4.

And in sheet: Source data,
an alternative to replace what you have in C6:E6
would be to place this in C6:
=SUMPRODUCT($B$2:$B$5,C2:C5)
and copy C6 across to E6

Btw, pl mark ALL responses which help you in any way by clicking the YES
buttons (like the ones below)
--
Max
Singapore
http://savefile.com/projects/236895
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xdemechanik
---
"americasrecycler" wrote:
Hi Max,

If you look at the invoice #, being changed and the "Qty" also changing with
the "Inv#" on sheet 1.

What I'm trying to do is to add multiple invoices (with diff. Qty and item
within those Qty ) in sheet 2

I understand that inorder to keep those result in real numbers, I have to
have different input sheet (similar to sheet 1) for each invoice, but that
would make the workbook overloaded (there are hundreds of invoices).

So my question is, is there any way to use only sheet one as data input for
all INV#, then add the total in sheet2 ???