Hi,
You cannot perform the 3D sum as you currently have it laid out. You would require (I am guessing at your other intermediary sheet names here):
=SUMPRODUCT(SUMIFS(INDIRECT("'"&{"June & Before","July","August","September","October","November","December"}&"'!F:F"),INDIRECT("'"&{"June & Before","July","August","September","October","November","December"}&"'!A:A"),"1342-79002570",INDIRECT("'"&{"June & Before","July","August","September","October","November","December"}&"'!C:C"),"Payment",INDIRECT("'"&{"June & Before","July","August","September","October","November","December"}&"'!I:I"),"0-60 days"))
Even better, since this is quite ungainly and inflexible, would be to go to Name Manager and create a new name, Sheet_Names say, with this in the Refers to: box:
={"June & Before","July","August","September","October","November","December"}
or whatever the actual sheets are in queston.
The formula then becomes:
=SUMPRODUCT(SUMIFS(INDIRECT("'"&Sheet_Names&"'!F:F"),INDIRECT("'"&Sheet_Names&"'!A:A"),"1342-79002570",INDIRECT("'"&Sheet_Names&"'!C:C"),"Payment",INDIRECT("'"&Sheet_Names&"'!I:I"),"0-60 days"))
That way, if ever you need to add/change/delete a sheet from the summation, you can simply make the necessary amendments in the defined name, and the formula will update accordingly.
Regards