[RESOLVED] Summing Running Totals?

I am having problems summing running totals.

Background:
I am working with Financial data, on occasion a customer will send us a check that is an overpayment to their account. When we report these back to our client we need to omit the overpayment and only show the transaction as it zero's out the account.

Below is the comments that explain how the code works and the code as it stands - its bugged so I am trying to fix it.

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Formula below prevents over payments on accounts.
If 2+ payments appear in the same date range and 1 payment results in an overpayment all transactions related to that account will appear as the balance that prevents the overpayment.

Eg. Don owes $130.00 Don makes 2 payments of $75 each, resulting in an overpayment of $20.00. Instead of showing 1 payment of $75.00 and 1 payment of $55.00, it will show 2 payments of $55. This results in it being $20 short on the reports.

This to try. Add a count against Artiva ID. If 2+ Artiva ID's that are equal are present in the reporting period, only make the change to the greatest Transaction Key

If {@Display Selection} = "Display" then
if {AFACCOUNT.AFACCURBALINT} >= 0 then
{AFSPLIT.AFSPAMT}*(-1)
else
({AFSPLIT.AFSPAMT}-{AFACCOUNT.AFACCURBALINT})*(-1)
else
0.00

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In an attempt to overcome its deficiencies I created a running total that counts the number of times an individual account ID appears on the crystal report.

I started writing the formula below just as a tester and it fails.

If {@Display Selection} = "Display" then
if (#num of aracid) >1 then
2

When I save that to test its results I get the following error:

A summary has been specified on a non-recurring field.
Details: @positive

@positive is the name of the formula to which I was modifying this code.
@positive is the positive version of all payments coming into our company and then in the footer of the group, there is a summary.

How can I prevent this error, and how can I sum this formula up and reference running totals?