Blog/Maritime & Shipping

Checking Port Disbursement Accounts (PDA vs FDA) Before You Pay

Compare PDA and FDA line by line against tariffs, services used and evidence, so you pay port costs that are correct and nothing extra.

By Sagar Makker · 5 min read · October 2026
In short
The PDA is the estimate and advance. The FDA is the final bill. Most errors hide in the gap.
Check each FDA line against the PDA, port tariffs, supplier invoices and the SOF.
Query variances with the agent before paying, and keep a history of costs per port.
The problem

The agent's final disbursement account arrives weeks after the vessel sailed. It is higher than the proforma. Some lines are clear, others say 'miscellaneous' or 'agency extras'. Launch hire appears twice. Overtime is charged for a weekend the SOF shows as working hours. With dozens of port calls a month, the accounts team approves most FDAs without checking.

Port costs are a significant line in voyage results, yet checking them is slow. Invoices arrive as scanned PDFs, tariffs differ by port, exchange rates vary, and the people who know what services were used are in operations, not accounts. Overcharges, duplicates and missing advance credits slip through and are rarely recovered later.

Why it happens
01FDAs approved against the PDA total rather than checked line by line
02Supporting invoices missing or unclear for third-party services
03Charges not compared to the SOF, so time-based costs go unchecked
04No cost history per port to tell normal charges from unusual ones
How to fix it
1
Standardise PDA and FDA lines
Map every agent's line items to one cost list: port dues, pilotage, towage, mooring, berth hire, launch, agency fee and others. This makes comparing PDA and FDA possible.
2
Compare FDA against the PDA
Line up each FDA item with its PDA estimate. Flag new lines, large variances and vague items like miscellaneous charges that need a clear explanation and invoice.
3
Check against evidence
Verify each charge against port tariffs, supplier invoices and the SOF. Confirm tug counts, launch trips, overtime hours and exchange rates match what actually happened.
4
Query, settle and record
Send the agent one consolidated query list. Pay only agreed amounts, net off the advance paid against the PDA, and store final costs to benchmark future calls.
Where an AI agent helps
Input
PDA, FDA, supplier invoices, port tariffs and the statement of facts
Agent does
Maps lines, compares PDA to FDA, checks charges against tariffs and SOF, drafts agent queries
Human gate
Operations or port cost analyst approves queries and the final amount to pay
Outcome
A checked FDA, agreed adjustments and a cost record for each port
What to measure
FDAs checked line by line before paymentVariance between PDA and FDA by portAmounts recovered after agent queriesDays from FDA receipt to settlement
Questions
What is the difference between a PDA and an FDA?

A proforma disbursement account (PDA) is the agent's estimate of port costs before the call, often used to request an advance. The final disbursement account (FDA) is the actual bill after the call, with supporting invoices, settled against the advance.

Why is the FDA often higher than the PDA?

Common reasons include longer stays, extra tugs or launches, overtime, changed berths, exchange rate movements and services added during the call. Some differences are legitimate. Others are errors or unsupported charges, which is why each variance should be explained.

Which FDA charges deserve the closest look?

Vague lines such as miscellaneous or sundries, duplicate services, overtime and time-based charges, third-party services without invoices and exchange rate conversions. Compare these against the SOF, tariffs and your own history for that port.

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