second, the way that I would break them up, isn't so much breaking them up as adding additional formulas to 'see' what the report is doing. Sometimes I add addional sections after my data so that I can review the values in the shared variables and can 'check' that my logic is correct.  You could create a section below the details, for example, and drop the group footer formulas on it to see the values as they are changing... you could add one before as well and see how the values change and if they are being initialized as you think they are.

 

HTH