How Automation Changes Peak Season Forecasting
Written by Johan Heij, Freight Reconciliation Subject Matter Expert
Every year around this time, the same conversation happens in finance. The Q4 forecast is due, freight is one of the biggest lines in it, and the honest answer to “What will freight cost us in December?” is usually: “About what it cost last December, plus a bit.”
The trouble is that peak season doesn’t follow the pattern of the rest of the year, and the volume of invoices makes it hardest to see what’s actually being billed.
Peak Season Changes the Price, Not Just the Volume
Volume goes up, and UPS has said it expects U.S. volume to climb about 24% from Q3 to Q4. The price structure changes as well. U.S. carrier peak charges started at the end of September and run into mid-January, the most expensive window runs roughly from Thanksgiving to the day after Christmas, and flat holiday fees are up 22 to 25% on 2025.
For high-volume shippers, the surcharge isn’t even a fixed amount. The tier depends on weekly volume compared with a June baseline, so a shipper at 250% of its baseline in early December pays $3.35 per Ground Residential package instead of $0.75, and above 400% it’s $8.00. FedEx calculates the peaking factor for one week and applies it two weeks later, contracted discounts and caps don’t apply, and fuel surcharges are charged on top of the demand surcharge as well.
The same pattern shows up outside the U.S. Purolator, Canada Post, bpost, and DHL Germany all add peak charges this season, and StarTrack’s fuel surcharge rose from 17.6% in September to 24.2% in November.
So the cost of a December shipment depends on how busy you were two weeks earlier, which surcharge window it landed in, and what fuel was doing that week. Last year’s run rate can’t capture that.
Where the Forecast Breaks
Most freight forecasts and accruals are still built backwards, from last month’s run rate, a percentage of revenue, or a logistics spreadsheet. Because the estimate isn’t tied to shipments, the variance lands in next month’s freight line unexplained, and margin is misstated in both periods. One industry source estimates that manual freight accruals commonly run 20 to 30% off the actual invoiced amounts.
Peak season makes that worse in three ways. Shipments from the last weeks of December are invoiced in January, after the books close, so the accrual is the only number finance has for them. Post-holiday returns ship inside the late-peak window, so they carry surcharges too. And a team that can spot-check invoices in August can’t keep up in December, because the leakage grows with volume.
That’s why the January true-up is usually when finance first learns what peak season cost
What a Forecast Built on Real Shipments Looks Like
Every shipment has an expected cost before its invoice arrives, so the December accrual comes from the shipments you actually made. When invoices land, every line is checked against that expectation, and at close finance can see exactly how much freight is still unmatched.
After the season, that matched history shows what peak surcharges actually added per package, by carrier, service, and week. It answers questions that used to be guesswork: which carriers and services drove the biggest variances, how much of the December accrual got trued up in January and why, and whether moving volume into the shoulder weeks would have changed the bill. Those answers become the starting point for next year’s forecast and for carrier negotiations.
How Freight Invoice Automation Gets You There
Freight Invoice Automation (FIA) runs inside Dynamics 365 Finance & SCM. Freight bills come from your WMS or D365, with or without the Transportation Management module, and carrier liability is accrued when the freight bill is created and reversed when the carrier invoice arrives. Invoices in EDI X12, EDIFACT, or CSV are matched against freight bills using configurable rules, with 99% accuracy, and discrepancies above your thresholds are flagged automatically. Integrations with FedEx, UPS, and DHL work out of the box.
Invoice numbers are checked on import, so a re-sent invoice doesn’t get paid twice, and built-in WIP reporting by carrier, shipment, and financial tag shows what’s still unmatched at close. The invoice, service, and delivery history it builds is the data behind next year’s forecast, whether the carrier is UPS, Purolator, or DHL.
Peak surcharges are published months in advance. What most teams can’t see is how they land on their own invoices, and I’d rather finance walk into January with a number it can defend than find out afterward.
See What Peak Costs You, Line by Line
Freight Invoice Automation matches carrier invoices to freight bills inside Dynamics 365, so peak costs get measured instead of guessed. Learn more