I have found that they announced on August 3 that priced will be reduced, but they did not officially said an exact day.
The tiers system in the app store connect do remain the same, it has not changed. Additionally when you test in Sandbox the prices are correct.
But in the NEWS they published in August 3, they announced in a PDF the changes, and I can see that those changes are already in place in the production environments on In App Purchases.
So they have made the change without changing sandbox and without changing the price tiers reference in the App Store? How could that be?
News about new decreased prices for UK and Euro Zone
New price tiers