You may also want to check the XE rate of the DATE OF POSTING, NOT the DATE OF TRANSACTION.

If a currency is volatile even a couple days apart it could make a big difference.

I dont know whether CapOne use Date of Posting to determine Xchange rate or Date of Transaction.

I know FIA, Chase and Citi all use Date of Posting instead of Date of Transaction.

In Spring of 2009, the Korea Won had WILD gyration, and I saw my exchange rates had more than 5 % difference on my FIA card.

Same happened again in June/July for Euro that directly affected Turkish Lira. Even my cash withdrawal from ATMs which the rate is always the moment of withdrawal - had again more than 5% difference among 3 withdrawals in 5 days.

So you may want to double check your statement before you come to that conclusion. Not saying you are wrong but it worth to make sure you are checking the correct date.

EDIT:

Ooops, I saw you have figured that out after all.