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Eight mistakes AI makes checking a rent roll when nobody checks its work
You can ask any AI to compare a rent roll with the leases. If nobody checks its work, it can easily make one of these mistakes.
And you probably won’t notice. The table looks neat, every tenant has a line, and the AI tells you the rent roll matches the leases.
Finding the mistakes is real work. A building with 20 tenants has hundreds of numbers and dates to compare. Any one of them can be taken from the wrong page or the wrong column, and the answer still looks finished. The only sure way is to check each one against the lease. By hand, that can take longer than the AI took.
Why these mistakes are hard to spot
A chat AI writes the answer that sounds most likely. It doesn’t go back to the lease to look again. When it can’t find something, it doesn’t leave a blank. It fills in something that fits, or says the two match. So a wrong answer looks just like a right one. Asking the AI to check itself doesn’t help much, because it checks with the same eyes that made the mistake.
A missed rent adds up. Every $1 a month of rent is $12 a year. If the building is priced at a 6% return, that $12 a year is worth $200 of the price.
The mistakes
These are only some examples. They are not every mistake an AI can make; there are many more. We picked these eight to show the kind of thing that goes wrong.
1. It reads the lease but misses the change to it
The lease says the rent is $38.50 a foot. A later amendment raised it. The AI compares the rent roll with the old lease. It finds a difference that isn’t real, and misses the one that is.
2. It doesn’t ask whether the lease allows each charge
The rent roll bills a tenant $895 a month for heat. But the lease says the landlord pays for heat. Unless someone checks every charge against the lease, a charge the lease doesn’t allow passes as income.
3. It doesn’t notice what isn’t billed
The lease says the tenant pays part of the property taxes. The rent roll doesn’t bill that tenant for taxes at all. The AI only looks at what the rent roll shows, so money the landlord is owed never comes up.
4. It points to a page that doesn’t say it
The AI says the security deposit is $9,294.58, “per Section 6 on page 3.” Page 3 is the rent table. It looks like proof, so nobody opens the lease to check.
5. It compares the wrong number
Many rent rolls show more than one number that looks like rent. One may be the whole monthly bill: rent plus taxes, electricity and heat. One may be the asking rent, not what the tenant pays. One may be the rent per foot. The lease sets only the rent. If the AI picks the wrong number, every comparison after it is wrong.
6. It says free rent is right when only part of it is free
The lease gives two months with no rent at all. The rent roll bills the rent in two parts, the office and the basement storage, and takes off only the office part. The AI sees a discount each month and says it matches. The tenant is still billed $1,406.25 a month it doesn’t owe.
It can also miss what free rent leaves out. Under some leases, the tenant pays no rent but still pays its share of operating expenses. The AI can give the tenant everything free when it should still be paying those expenses.
7. It compares a lease with the wrong tenant’s line
The rent roll and the lease often name the same space differently. The property’s system writes “05-502-3”, its code for suites 502 and 503 on the fifth floor. The lease just says “Suites 502 and 503”. Now say the same company has a second lease, for a suite on the eighth floor. There are two lines on the rent roll with that company’s name, and two leases. The AI can pair the fifth-floor lease with the eighth-floor line. Then every number it checks for that lease, the rent, the size, the dates, is checked against the wrong space.
8. It leaves tenants out
A good check accounts for every line of the rent roll and every lease you sent. The AI often only compares the tenants it can match and quietly skips the rest. Say the rent roll lists 30 suites and you sent 27 leases. Three suites on the rent roll have no lease in your files: are those tenants real, and what did they sign? One lease you sent isn’t on the rent roll at all: is that tenant being billed? Two suites are empty. The AI reports on the tenants it matched and says nothing about these six, so the questions that matter most never get asked.
What to do about it
You can catch most of these yourself if you check the AI’s answer against the leases and the rent roll, not by asking the AI. Here are seven checks you can do yourself.
Or let us do it. Every rent roll reconciliation we deliver is checked by our own software. It checks every rent roll line, every lease term and every number against your documents before it reaches you. Each difference shows both numbers and the lease’s own page and words. Anything your documents don’t answer, we ask you. We never guess.