A CAM true-up lands in the client's inbox on a Tuesday in February. It is a $22,400 additional charge for the prior calendar year. The client is a 12-person law firm occupying 4,200 square feet in a downtown office building. They were estimating $1,200 per month in CAM, or about $14,400 for the year. The true-up says the actual was $36,800. For more context, see the accounting firm hub.
The client forwards it to you with two words: "Is this right?"
That is the fractional CFO's moment. Not the bookkeeper's. Not the controller's. Yours.
CAM Reconciliation Statement: An annual accounting from the landlord comparing estimated CAM payments collected from tenants against actual operating expenses incurred during the year. The result is either an additional charge or a credit to each tenant.
First Move: Size the Variance Before Saying Anything Else
Before you respond to the client, do the math. The law firm paid $14,400 in monthly CAM estimates during the year. The reconciliation says actual costs were $36,800 for their share. That is a $22,400 variance, which is 156% above what was estimated.
That number is the starting point, not a conclusion. Variances that large happen for legitimate reasons: a major roof replacement, a property tax reassessment, an insurance premium spike. They also happen because the landlord made a math error, included ineligible costs, applied the wrong pro-rata share, or failed to gross up during partial occupancy.
Your first job is to determine whether the variance is explainable before advising the client what to do with it.
What to Request Before Advising Payment
Do not advise payment on a material true-up without supporting detail. The reconciliation statement is a summary. The backup is the building's operating expense ledger, broken down by cost category.
Request the following from the landlord in writing:
The full expense reconciliation showing each cost category, the total building cost, and the tenant's allocated share. The pro-rata share calculation showing how the tenant's percentage was derived, including which square footage figures were used. Any capital expenditures included in the recovery, since most leases exclude capital items from CAM. Management fee calculation detail, since management fees calculated on gross revenues rather than CAM expenses are a common overcharge.
For the law firm example: a $1,200/month estimate suggests someone set the CAM estimate at the start of the lease and may not have updated it. The $22,400 variance may be entirely legitimate, or it may reflect three or four years of understated estimates that the landlord is now collecting. Either way, you need the backup.
The Client Conversation: What It Is and What the Options Are
Once you have sized the variance and decided whether to review before advising payment, you need to frame the situation for the client. Do not lead with alarm or with reassurance. Lead with facts and options.
Here is how that conversation goes: "You received a CAM reconciliation for last year. The landlord calculated that actual building operating costs allocated to your space were $36,800, and you paid $14,400 in monthly estimates, so they are billing the difference of $22,400. That is a larger-than-usual variance. Before you pay it, I want to request the backup detail to confirm the calculation is correct. You likely have 30 to 60 days to review it before payment is required. Here are your options."
Then give them three options: pay now if the client trusts the landlord and does not want to spend time on it; review with backup before paying; or refer for a formal audit if the amount justifies it.
The law firm with $22,400 at stake almost certainly wants option two or three. A 3-location retailer receiving three true-ups totaling $18,000 across their portfolio may have a lower threshold for triggering an audit given the cumulative exposure.
When to Escalate for a Formal Review
The threshold question is whether the variance justifies the cost of a formal review. I built CAMAudit because fractional CFOs and their clients were constantly in this position: a large, suspicious bill with no easy way to check whether the math was right.
The signals that a formal review is warranted include: a variance exceeding 20% of the annual estimate; a management fee that appears to be calculated on a base that includes taxes and insurance (which inflates the fee); a pro-rata share that does not match the tenant's lease; prior year true-ups that also seemed high; or a lease renewal coming up where billing history matters for negotiation.
A law firm in a lease renewal window has extra reason to care. A billing pattern that shows consistent overbilling is negotiating leverage. A formal audit that recovers a prior overcharge is also leverage.
Cash Flow Impact and How to Model It
The cash flow dimension of a CAM true-up is straightforward if you model it, and painful if you do not. A $22,400 charge hitting in February is a $22,400 cash outflow that was not in the Q1 forecast.
The right response is to build occupancy true-up uncertainty into the model from the start of the year. Estimate the prior year true-up based on known cost trends: property tax reassessment notices, insurance renewal communications, any landlord notifications about capital projects. Flag the estimate as uncertain with a low and high scenario.
For a multi-location client, run this exercise for every location. Three locations with $6,000 average true-up risk each gives you an $18,000 occupancy variance bucket in the forecast. That is not a precise number, but it is honest, and it prevents the February call where the client asks why the cash balance is $22,000 lower than projected.
When the actual true-up arrives and it is larger than the estimate, update the forecast immediately and walk the client through the bridge: what was estimated, what was actual, what changed. That is the advisory value.
When Delaying Payment Is the Right Call
Most leases include an audit rights clause that gives tenants a defined period to review a reconciliation statement before the payment is deemed final. Common windows are 30, 60, or 90 days from statement receipt. Some leases allow tenants to withhold disputed amounts during an audit.
Advising a client to delay payment is reasonable when: the backup has been requested and not received; a review is actively in progress; the amount in dispute is material and the lease supports withholding. It is not reasonable to delay indefinitely, and you should track the audit deadline closely.
One critical note: some leases treat payment as acceptance. If the client pays the full true-up amount without reservation, they may lose the right to dispute it. For a $22,400 charge, it is worth a quick read of the lease audit rights clause before the check goes out.
The Advisory Product You Are Already Positioned to Offer
The fractional CFO is already the client's trusted advisor on cash flow and financial decisions. Adding CAM review to that workflow is not a scope extension. It is a natural part of managing occupancy cost, which for most small businesses is the second or third largest expense category.
The question is whether you have the right tools to do it efficiently. Reviewing a CAM reconciliation manually, line by line, against the lease requires time and lease expertise. Referring it to a specialist who uses a structured audit tool means you can offer the service without building the internal capability from scratch.
The value to the client is the same either way: someone checked the math before the check was written.