Seven overcharge patterns. Every TSA has at least three.

Rate card drift and volume baseline error.

The first pattern is rate card drift. The TSA specifies a rate per unit. The invoice charges a different rate. Sometimes higher by a defined index adjustment that the seller has applied without notice. Sometimes higher because the seller's billing system was updated and the new rate card was not approved. The reconciliation is straightforward. The invoice rate is compared to the contract rate. Differences without a contractual basis become recovery items.

The second pattern is volume baseline error. The catalog specifies a volume for each service, based on what Newco consumed in the year before signing. The invoice charges against a different volume. Sometimes higher because the seller has billed against estimated rather than actual consumption. Sometimes higher because the seller has not updated the baseline as Newco's usage has shifted.

Both patterns are visible in the invoice reconciliation. The buyer pulls the contract rate card and the consumption baseline. The buyer compares the invoice line by line. Variances generate questions. Most resolve within 30 days of the formal query. Some require formal credit claims.

These two patterns alone account for 30 to 50 percent of total overcharge recovery on a typical TSA. The reconciliation pattern overlaps with the discipline in TSA cost reduction tactics, which catalogues how disciplined buyers maintain ongoing invoice review.

Service that has been terminated still appearing.

The third pattern is the terminated service that continues to appear on the invoice. The buyer terminated the service under the TSA notice period. The notice period elapsed. The service stopped being delivered. The invoice continues to bill for it. This is often an administrative lag rather than a deliberate overcharge. The recovery is the same. The buyer notes the termination notice date, the service stop date, and the period of incorrect billing.

The seller's response usually concedes the overcharge within one billing cycle. The credit is applied retroactive to the service stop date. The line is removed from the catalog going forward. Where the seller resists, the buyer references the termination notice and the contractual basis on which the service ended.

This pattern appears most often during workstream exits. Multiple lines terminate in the same week. The seller's billing operation processes some, misses others. The disciplined buyer maintains a termination log against every invoice and catches the missed terminations within 30 days. The broader sweep mechanism sits in TSA stranded cost elimination.

The compounded cost of missed terminations is significant. A workstream that terminates in month four but continues to bill for another six months represents nine months of unjustified charges if not caught.

Pass-through mark-up and allocation inflation.

The fourth pattern is mark-up applied to pass-through. Pass-through pricing is supposed to be at cost. The invoice shows a higher number than the underlying third-party invoice. The difference is hidden mark-up. The reconciliation that catches it sits in the pass-through audit, but the pattern can also be spotted on the invoice when the buyer has access to the underlying third-party pricing through other means.

The fifth pattern is allocation inflation. The seller's third-party contract covers multiple business units. The allocation methodology determines Newco's share. Sellers sometimes inflate Newco's share through allocation factors that overstate consumption. The pattern is harder to spot on the invoice alone. The audit that catches it documents the methodology and reconciles it against actual consumption.

The full diagnostic for these two patterns is in TSA vendor cost pass-through audit. Together they typically represent 20 to 30 percent of total overcharge recovery on a TSA with significant pass-through.

The pattern recurs because the seller's billing operation is structurally separated from the seller's third-party vendor relationships. The data that would catch the overcharge sits in two different systems. The audit forces them together. The recovered cost is the gap between the two.

Duplicate billing and ghost line items.

The sixth pattern is duplicate billing. The same service appears on the invoice twice under different descriptions. This happens when the catalog has multiple entries for what is operationally a single service, or when the seller's billing system pulls the same charge from two different source systems. The reconciliation against the catalog catches this immediately. The buyer requests the seller to map both lines to the catalog source and the seller acknowledges and credits the duplicate.

The seventh pattern is the ghost line item. The invoice contains a charge that has no corresponding catalog entry. The seller cannot point to a specific service this line corresponds to. The line exists in the seller's billing system as a historical entry that survived the carve-out separation. The buyer requests documentation. The seller either produces it or removes the line.

Both patterns are typically administrative rather than deliberate. They reflect the messiness of the seller's billing system rather than any commercial intent. The recovery is straightforward once flagged. The discipline is that the buyer flags them at all. Most buyers do not, because the invoice review is cursory and the lines do not stand out.

A formal monthly invoice review by a finance analyst catches all seven patterns. The review takes two to four hours per invoice for a typical TSA. The recovery on a $20M annual TSA averages $400K to $1M per year against the unmitigated invoice. The pattern of cleanup that follows is covered in TSA shadow billing.

The monthly review methodology.

The monthly review starts with three documents. The current invoice. The previous month's invoice. The contract rate card and catalog. The reviewer compares each invoice line against the catalog entry, against the rate card price, and against the previous month's equivalent line. The four data points together flag every overcharge pattern.

Each variance is documented in a query log. The query log goes to the seller within five business days of invoice receipt. The seller has 30 days to respond. Responses are tracked. Conceded queries become credit memos. Disputed queries enter the formal resolution process. Unanswered queries become escalations.

The discipline is what produces the recovery. A one time audit at the end of the TSA recovers a fraction of what a monthly review captures continuously. The seller's billing rhythm also improves over time. After two or three months of structured queries, the seller's invoices arrive cleaner. The patterns reduce because the seller's billing team learns that the buyer is reviewing carefully.

The monthly review is the operating practice that makes the TSA cost number real. Without it, the TSA bill is whatever the seller decides to charge and the buyer pays. With it, the bill aligns with the contract. The same discipline runs the TSA true-up management exercise at the annual reconciliation.

How to escalate disputed overcharges.

Most queries close within 30 days of submission. Some disputed items escalate. The escalation path is set out in the TSA. The first step is usually a written dispute notice from the buyer's program director to the seller's TSA lead. The notice references the specific invoice lines, the contractual basis for the dispute, and the requested remedy.

The second step is the governance committee. The dispute moves to the joint forum that meets monthly. The committee has authority to resolve commercial disputes within the TSA. Most disputed overcharges settle at the committee meeting because both parties prefer settlement over formal escalation.

The third step is the formal dispute resolution clause. Mediation, arbitration, or litigation depending on the contract. Most TSAs include mediation as the required first formal step. Mediation typically resolves within 60 to 90 days at moderate cost. Arbitration is rarely needed. Litigation is the option of last resort and is almost never used in TSA disputes because the commercial relationship is by definition time limited.

The escalation discipline matters because it sets the buyer's posture. A buyer that escalates disputed overcharges to the committee establishes that overcharge claims are taken seriously. A buyer that lets disputed items sit unanswered teaches the seller that the queries can be ignored. The posture compounds over the term of the TSA.

More on TSA cost reduction.