实际上这似乎只发生在沙盒中。所以生产很好。
我在NL和FR商店测试过它。另一位开发商在DE商店证实了这一点。

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Adding in-app purchase for a ios app. I could successfully purchase the product but "Confirm Your In-App Purchase" dialog always shows extra price compared to my formatted localised price.

Example: A localised price for a product is 39.99 Euros, but when in the confirmation dialogue box, the price of the product is increased to 41.73 Euros.

Thanks in advance for any solutions for this issue.

Actually it seems this is only happening in the sandbox. So the production is fine. I've tested it on the NL and FR store. Another dev confirmed the same from the DE store.

If you have access to the Apple developer forums, more details in this thread: https://devforums.apple.com/thread/259099?tstart=0

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Outdated?

Still researching a proper solution but here is the first part of this answer.

Apple is required by EU regulation to charge tax based on where the customer is located, not the company's Euro HQ.

An in-app purchase of € 3,99 (Tier 4) is now € 4,34 in NL.

news source: http://www.theverge.com/2015/1/8/7518085/apple-app-store-price-increase-europe-canada

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Still working on how to show the customer the price + tax.

SkProduct does not seem to have a tax property so it might need to be calculated. There's no property that provides the tax value.

https://developer.apple.com/library/prerelease/ios/documentation/StoreKit/Reference/SKProduct_Reference/index.html