Today I tried to reconcile the payments my client had made to different tax debts. I used IRS transcripts from the IRS to see all of the payments he made over several years. It was just like the scene in the Harry Potter movie where there is a maze that changes as you proceed. We had requested that the IRS provide us a list o the money obtained from the levy of my client's customers. Almost none of the payments received from the customer matched the IRS transcripts. The IRS randomly groups payments. Sometimes, the payments are posted to one year then partially removed and posted in another year. If that cause an overpayment the payment may then be moved to another year or tax period. It is very frustrating.
The IRS provides account transcripts to taxpayers that request the transcripts. The transcripts will often have the IRS computer codes on each entry. Many of the codes are hard to find on the IRS website.
Reconciling the payments made to the transcripts gives you an opportunity to find lost money. It is bad enough to owe the IRS for tax from several taxable years or periods. It is even worse when some of the payments can not be found on your transcript.
The IRS records numbers on the back of your check when the money is received. However, it is almost impossible to find out where they stuck the money without the cancelled check. Cashiers checks and money orders do not come back to you. The original is at the issuer and so is the tracing number. Use your own checks when paying IRS debt.
You can request that the IRS provide you with a schedule showing how much was received from a levy of your bank or your customers. Your customers will be upset that they were forced to send the money that was owed by you to the IRS. They will be even more upset if you bill them incorrectly because you can't see how much the IRS was paid. Many customers are lost because of the corrosive effect on the relationship with the customer because of the intimidation of future levies.