Dennis @ PerfectForms
I think you are saying that you want a report that shows you for each individual employee the value in the balance field from the most recently submitted instance. Correct?
If that is the case, I would use a form connection and a hidden table in my report. Create a connection to your Leave Application form. Send parameter = name, return parameter = Balance, and Name. When the report opens use the connection to populate a drop-down with all of the names in the form instances (leave send parameter value empty). When that drop-down changes data use a Connection to send the name in the drop-down and return the balance to all rows of the table. Then use a Set Table Rows to go to the last row (most recent instance) and finally use a Set Field to set a field in the report with the value in the current row (the balance value from the last instance for that person).