I am using a subReport to handle a one-to-many data issue.  And, it is working fine returning data on a 2nd Detail line - so my shared variable is read/processed after the subReport.

However, I cannot 'sum' on the field.
My field in report is like:
// @subAsthma
WhilePrintingRecords;
Shared NumberVar srxAsthma;
srxAsthma

So, while printing detail records, I correctly show who has Asthma. (There is a 1 in the field.)

But, it is not in the list of fields that I can sum/count on for my Group and Report level breaks.

I think I can create a running-total field for this; actually two since I will need one for Group (and need to reset in Group Hdr) and one for Report.  Possibly an ok solution, but I envision passing 20 or so data values from subReport.

So, any insight into why some Formula Fields are eligible for sum/count and others are not?