When filing reimbursement claims, the amount for which you are seeking reimbursement should equal the final amount that was paid, which should also equal the combined amounts for each of the treatments that were provided on the date of service.
If multiple treatments were rendered during a visit, and a discount was applied to the sum of all the fees (the sub-total), then the discount should be deducted evenly across each of the fees for each of the services rendered.
For instance in a visit where two services were rendered, if Service 1 had a fee of $100, and Service 2 had a fee of $200, and a discount of $50 was applied to the subtotal, then the total amount paid would be $250 (rather than $300). This is effectively a 17% discount.. Therefore, 17% should be deducted from the Service 1 fee ($83 after the discount was applied) and the Service 2 fee ($166 after the discount was applied). As you'll note, $83 + $166 = $249, not $250. In this case, an extra $1 should be added to the fee paid for either Service 1 or Service 2, so that the total amount paid is equal to the total amount for which reimbursement is sought.
Here's another example where applying the discount percentage evenly across multiple units might result in a calculation that is a few pennies over or under the amount that you paid. Let's say you receive a treatment that requires 4 units at $33.75 for a total of $135. A 10% practitioner discount makes the total $121.50. In this case the per unit price becomes $30.375, meaning the total rounded down is $121.48 or $121.52, if rounded up. In this case you should round down, so that the total amount for which you are seeking reimbursement is a couple of pennies less than what you actually paid.