An invoice discrepancy occurs when invoice details—such as pricing, quantities, supplier details, or payment terms, don’t match what was approved (for example, a purchase request, PO↗, contract, or agreed terms). For fast-growing companies, these mismatches quickly become a high-risk accounts payable (AP) issue. As invoice volumes rise and approvals span more teams, even tiny inconsistencies can delay payments, strain supplier relationships, and lead to duplicate or incorrect payouts.
This guide breaks down types of invoice discrepancies and early warning signs. It also shows how tools like Moss support accuracy and control as companies scale.
Common types of invoice discrepancies
Here are a few common types of discrepancies that tend to pop up as companies scale, often linked to transaction volume and handoffs between teams.
- Overcharging occurs when a supplier invoices a unit price higher than what appears in the PO↗ or contract. For example, a team agrees to £12 per unit, but the invoice lists £14 per unit.
- Undercharging means a supplier bills for less than the agreed amount. While this may seem minor initially, it creates reconciliation gaps if the supplier submits a follow-up invoice later.
- Incorrect billing details refers to an invoice including incorrect information, such as the legal company name, address, or VAT number. These errors create compliance risks and delay approval because the invoice cannot be processed as submitted.
- Duplicate invoices happen when a supplier submits the same invoice more than once, often by sending one copy via email and another through a portal. As invoice volumes increase, duplicates are more likely to slip through without standardised checks.
- Unauthorised or missing charges means unapproved line items appear, or previously approved charges are missing. These invoices require additional review and clarification before payment.
Root causes of billing and payment discrepancies
As teams expand, missteps can happen simply because workflows aren’t fully aligned. Below are some of the recurring discrepancies to watch for, along with why they happen.
Errors in data entry
Many teams still manually enter information from emails, spreadsheets, and ERP records↗, but this approach breaks down quickly as invoice volume grows. Small typos and mismatched fields can lead to larger payment discrepancies, especially when multiple tools hold different versions of the same data.
Communication gaps between departments
Procurement, budget owners, and AP teams↗ often work from different assumptions about what companies ordered or approved. This generally happens because each team sees only part of the process or receives information in different formats. For example, a supplier may invoice based on one set of details, while the internal team expects another. Shared visibility across departments helps prevent these irregularities.
Software and technology issues
When invoice software, ERPs, and approval workflows lack a single source of truth, inconsistencies surface. Factors such as outdated tax details and incorrect currency settings all contribute to billing discrepancies during reconciliation.
How to identify invoice discrepancies early
Early detection protects cash flow↗ and reduces rework. It also helps maintain supplier trust, which becomes more important as payment volume grows. Let’s look at some common ways finance teams catch gaps before they turn into bigger problems.
Regular audits
Spot checks by vendor or department surface unusual patterns. These reviews reveal repeated errors from the same supplier or workflow stage.
3-way matching
Three-way matching↗ compares the PO, receipt, and invoice. When they align, payment proceeds. A mismatch, on the other hand, triggers a review before any money moves. Moss scans uploaded invoices and pre-fills key invoice data, then automatically routes invoices through your approval flow. If you use purchase requests, Moss can automatically match an uploaded invoice to the corresponding purchase request to support review and approval.
Approval rules and thresholds
Clear thresholds help auto-flag anything outside expected amounts. For example, if a price exceeds the approved value, the system routes the invoice for human review rather than pushing it through.
Automated discrepancy checks in AP tools
Automation plays a major role in preventing errors. AP tools like Moss automatically extract and pre-fill relevant invoice data (with accountants or admins reviewing and confirming details during the invoice review step), match uploaded invoices to the corresponding purchase request (where used), and maintain audit logs. This shift means teams can proactively prevent problems instead of reacting to issues after payment.
3 effective steps to resolve invoice discrepancies
Scaling finance teams↗ handle challenges more easily when they follow consistent steps. Clear invoice processes keep communication smooth and prevent rushed approvals. Here are three practical steps teams can take to resolve these issues efficiently.
- Establish a standardised resolution process
Set clear roles for reviewing and communicating with suppliers. Share timelines, escalation steps, and a single place to log issues so everyone stays aligned. Avoid paying invoices just to move them forward — sticking to a steady process protects the team from bigger problems down the line.
- Engage stakeholders quickly
Loop in procurement, key stakeholders, and suppliers as soon as something looks off. Early visibility speeds fixes and keeps payments on track.
- Document and follow-up consistently
Keep concise records of what happened and how the team resolved each issue. These notes make future reviews easier and help prevent repeated errors.
Best practices to prevent future billing discrepancies
As invoice volume grows, preventing issues becomes harder. By making small adjustments to the process, finance teams stay in control without slowing down daily work. Here are a few strategies to keep invoice processes running seamlessly and avoid errors:
Invest in training and role clarity
Ensure teams share a basic understanding of POs, expense coding, and approval steps. Regular training sessions keep everyone aligned as the company grows.
Define clear workflows and responsibilities
Assign roles clearly so invoices move with fewer errors. Simple workflows cut down on confusion and keep the overall process steady.
Maintain clean, up-to-date systems
Keep vendor details, tax information, and coding rules current to minimise errors and prevent delays or mispayments. Additionally, sync ERPs and AP tools to reduce discrepancies during review.
Strengthen internal controls
Implement approval matrices, spending thresholds, and three-way matching↗ to catch problems early. These controls also highlight recurring issues so leaders can update policies as needed. Teams can track metrics like discrepancy rates or resolution times to get a sense of long-term progress. Plus, applying strong cost control↗ gives teams clear visibility into problem areas and process improvements.
Strengthening AP processes for long-term confidence
Companies that scale quickly see invoice volumes surge. Controlling discrepancies protects cash flow, maintains accurate records, and preserves supplier relationships. Detecting issues early and applying strong controls keeps AP running smoothly.
Moss↗ helps scaling finance teams handle the busywork behind the scenes. Automated invoice capture, clear approval routing, built-in tracking and detailed audit logs minimise manual effort and make discrepancies easier to spot and prevent.
You can download an audit log PDF from the ‘Comments & Activity’ section of an expense, and exported expenses include the audit log as an attachment.
Book a demo today↗ to see how Moss helps your teams maintain comprehensive audit trails across AP.
