The employee attendee Expense Policy - not working as expected

We have a requirement on Attendee expense policys, Our client is expecting the expense report should not to show the error until the total amount of dollars assigned to the employee

For Exp: if they add 2 users 1 user they assigns 40 dollars and another user add 40 dollars ,then the expenses report should not show the error until the remaining 20 dollars are assigned to the employees