Hello, Yasar. Welcome to the Community space,

Let me provide info on why the landed cost isn't calculating after pressing the "Post To Bill" button.

There are several reasons why the landed cost isn't calculating when trying to post it to the bill. Check the list of reasons below: 

• The bill is missing inventory and assembly items.
• The inventory and assembly item bills are open or another user is working on it.
• The currency of the cost is different.

Since you're using multiple currencies option and your home currency is AED, ensure to associate a specific currency when adding a vendor. Here's how:

1. Select Vendor Center from the Vendors tab.
2. In the Vendor Center, select the New Vendor dropdown or click the profile of the vendor you want to associate a currency.
3. Edit or enter vendor details and assign a Currency. 
4. Once done, click OK.

Also, you can read this article to check if landed cost is calculated accurately: Landed cost FAQs.

If you want to update some of your selling prices based on landed cost, check out this article: How to calculate landed cost in QuickBooks Enterprise Services.

Let me know if you have additional questions about managing your landed cost feature. We'll be willing to lend a hand. Keep safe, and have a good one.