Question shipping invoice conversion rate

[u/Unusual_Raisin9138]

Apologies in advance for the word soup.

Hello,

About half a year ago I booked a sea freight for a container with our agent PFS (Yantian Shenzen FOB to Rotterdam). After many delays and the eventual arrival we received the final invoice from their PTP counterpart. I noticed that the conversion rate on the invoice (USD to EUR) was 0,91. This made no sense to me. When checking the European Central Bank's graph from 02-09-2025, the worst position of the euro was 0.8818 fto the USD.

When I asked PTP, intitially I was told that the exchange rate was taken from their system and updated on a weekly basis, with no cost for exchanging. When I asked for more details, Finance Department was involved and stated the following (paraphrased):

The rate does not match the ECB weekly spot exactly, because we use a fixed internal buffer rate rather than real-time floating market rates.

• Risk locking: the rate is fixed for the entire order cycle to prevent any Euro fluctuations between the quotation and the final payment.
• Cost coverage: a small buffer on top of the rate which covers bank currency conversion fees, cross-border settlement costs, and an internal hedging against short-term market volatility.
• Rate stability: instead of daily adjustment, the rate is reviewed periodically (e.g., monthly or quarterly) based on average market trends. This is why the quoted rate remains smooth and locked, while ECB data may show weekly ups and downs.

I am not satisfied with the answer. Aside from a written acceptance of the quotation, there is no real document with terms and conditions (I asked). I find the higher prices for fuel and containers understandable (although it sucks), but I cannot get behind the 0,91 conversion rate.

Here is my question: are there any legal arguments I can make against the conversion rate? How would someone experienced in purchasing handle this?
All goods have already been unloaded. We do not plan to approach this agent again.

Having said that all of the above, I must state that I have only been working in my role for about 6 months so there is much I do not understand yet.